Triangle Height

🏆Practice parts of a triangle

Set the Height of a Triangle

The height of a triangle is the segment that connects a vertex to the opposite side such that it creates a 90-degree angle.

In every triangle, there are three heights, as there are three vertices from which the height can be calculated relative to the side that is opposite to each of them.

The height can be found either inside or outside of the triangle. If it does not run through the interior of the triangle, it is called an external height.

Below, we provide you with some examples of triangle heights:

A1 - triangle height

Start practice

Test yourself on parts of a triangle!

Is DE side in one of the triangles?
AAABBBCCCDDDEEE

Practice more now

If you're interested in learning more about other triangle topics, you can check out one of the following articles:

  • Acute Triangle
  • Obtuse Triangle
  • Scalene Triangle
  • Equilateral Triangle
  • Isosceles Triangle
  • Edges of a Triangle
  • Area of a Right Triangle
  • How to Calculate the Area of a Triangle
  • How is the Perimeter of a Triangle Calculated?

On the Tutorela blog, you'll find a variety of mathematics articles.


Triangle Height Calculation Exercises:

Exercise 1

Given the parallelogram ABCD ABCD

CE is the altitude from side AB AB

CB=5 CB=5

AE=7 AE=7

EB=2 EB=2

Image of Exercise 1 Given the parallelogram ABCD

Task:

What is the area of the parallelogram?

Solution:

To find the area, you must first determine the height of the parallelogram.

For this, let's take a look at the triangle EBC \triangle EBC ,

Why do we know it's a right triangle? Because it's the height of the parallelogram.

We can use the Pythagorean theorem: a2+b2=c2 a^2+b^2=c^2

In this case: EB2+EC2=BC2 EB^2+EC^2=BC^2

Substituting the given information: 22+EC2=52 2^2+EC^2=5^2

Isolating the variable: EC2=5222 EC^2=5^2-2^2

And solving: EC2=254=21 EC^2=25-4=21

EC=21 EC=\sqrt{21}

Now, all we have to do is calculate the area.

It's important to remember that this requires using the length of side AB AB ,

That is, AE+EB=7+2=9 AE+EB=7+2=9

21×9=41.24 \sqrt{21}\times9=41.24

Answer:

41.24 41.24


Join Over 30,000 Students Excelling in Math!
Endless Practice, Expert Guidance - Elevate Your Math Skills Today
Test your knowledge

Exercise 2

Given the right triangle:

Exercise 2 Given the right triangle

Task:

What is the length of the third side?

Solution:

The image shows a triangle of which we know the length of two of its sides and we want to find the value of the third side.

We also know that the triangle shown is a right triangle because a small square indicates which angle is the right angle.

The Pythagorean theorem states that in a right triangle the following applies:

c2=a2+b2 c²=a²+b²

In our right triangle

a=3 a=3

b=4 b=4

c=x c=x

When we replace the values of our triangle into the algebraic expression of the Pythagorean theorem, we get the following equation:

x2=32+42 x²=3²+4²

x2=9+16 x²=9+16

x2=25 x²=25

If we now take the square root of both sides of the equation we can solve for x x and obtain the desired value

x=25 x=\sqrt{25}

x=5 x=5

Answer:

x=5 x=5


Exercise 3

Homework:

How do we calculate the area of a trapezoid?

We are given the following trapezoid with these features:

We are given the following trapezoid with these features

What is its height?

Solution

Trapezoid area formula:

(Base+Base)2×height \frac{(Base+Base)}{2}\times height

The formula is not displaying correctly on the page.

9+62×h=30 \frac{9+6}{2}\times h=30

And we solve:

152×h=30 \frac{15}{2}\times h=30

712×h=30 7\frac{1}{2}\times h=30

h=30152 h=\frac{30}{\frac{15}{2}}

h=6015 h=\frac{60}{15}

h=4 h=4

Answer:

Height BE BE is equal to 4 4 cm.


```

Do you know what the answer is?

Exercise 4

Given the isosceles triangle ABC \triangle ABC .

And within it, we draw EF EF , parallel to CB CB :

Given the isosceles triangle ABD

AF=5 AF=5

AB=17 AB=17

AG=3 AG=3

AD=8 AD=8

A A is the height of the triangle.

What is the area of EFBC EFBC ?

Solution:

To find the area of the trapezoid, it is worth remembering the formula for its area: (base+base)2×height \frac{(base + base)}{2}\times height

We focus on finding the bases.

To find GF GF , we will use the theorem of Pythagoras: A2+B2=C2 A^2+B^2=C^2 in triangle AFG \triangle AFG

Replace:

32+GF2=52 3^2+GF^2=5^2

Isolate GF GF and solve:

9+GF2=25 9+GF^2=25

GF2=259=16 GF^2=25-9=16

GF=4 GF=4

We proceed with the same process with side DB DB in triangle ABD \triangle ABD :

82+DB2=172 8^2+DB^2=17^2

64+DB2=289 64+DB^2=289

DB2=28964=225 DB^2=289-64=225

DB=15 DB=15

From here there are two ways to finish the exercise:

  1. Calculate the area of the trapezoid GFBD GFBD and verify that it is equal to trapezoid EGDC EGDC and add them together.
  2. Use the data we have discovered so far to find the parts of the trapezoid and solve.

We start by finding the height GDGD :

GD=ADAG=83=5 GD=AD-AG=8-3=5

Now, let's reveal EF EF and CB CB :

GF=GE=4 GF=GE=4

DB=DC=15 DB=DC=15

This is because in an isosceles triangle, the height divides the base into two equal parts.

Therefore:

EF=GF×2=4×2=8 EF=GF\times2=4\times2=8

CB=DB×2=15×2=30 CB=DB\times2=15\times2=30

We replace the data in the trapezoid formula:

8+302×5=382×5=19×5=95\frac{8+30}{2}\times5=\frac{38}{2}\times5=19\times5=95

Answer:

95 95


Exercise 5

Given the isosceles triangle ABD \triangle ABD ,

Within it, EF is drawn:

AF=5 AF=5

AB=17 AB=17

AG=3 AG=3

AD=8 AD=8

Given the isosceles triangle ABD

Task:

What is the perimeter of the trapezoid EFBCEFBC ?

Solution:

To find the perimeter of the trapezoid, we need to add up all its sides.

We will focus on finding the bases.

To find GF GF , we will use the theorem of Pythagoras: A2+B2=C2 A^2+B^2=C^2 in triangle AFG.

We substitute:

32+GF2=52 3^2+GF^2=5^2

We isolate GF GF and solve:

9+GF2=25 9+GF^2=25

GF2=259=16 GF^2=25-9=16

GF=4 GF=4

We operate the same process with side DB in triangle ABD \triangle ABD :

82+DB2=172 8^2+DB^2=17^2

64+DB2=289 64+DB^2=289

DB2=28964=225 DB^2=289-64=225

DB=15 DB=15

We start by finding side FB FB :

FB=ABAF=175=12 FB=AB-AF=17-5=12

Now, we reveal EF EF and CB CB :

GF=GE=4 GF=GE=4

DB=DC=15 DB=DC=15

This is because in an isosceles triangle, the height divides the base into two equal parts.

Therefore:

EF=GF×2=4×2=8 EF=GF\times2=4\times2=8

CB=DB×2=15×2=30 CB=DB\times2=15\times2=30

What remains is to calculate:

30+8+12×2=30+8+24=62 30+8+12\times2=30+8+24=62

Answer:

62 62


Check your understanding

Examples with solutions for Triangle Height

Exercise #1

Is DE side in one of the triangles?
AAABBBCCCDDDEEE

Video Solution

Step-by-Step Solution

Since line segment DE does not correspond to a full side of any of the triangles present within the given geometry, we conclude that the statement “DE is a side in one of the triangles” is Not true.

Answer

Not true

Exercise #2

The triangle ABC is shown below.

To which side(s) are the median and the altitude drawn?

AAABBBCCCDDDEEEFFF

Step-by-Step Solution

To solve the problem of identifying to which side of triangle ABC ABC the median and the altitude are drawn, let's analyze the diagram given for triangle ABC ABC .

  • We acknowledge that a median is a line segment drawn from a vertex to the midpoint of the opposite side. An altitude is a line segment drawn from a vertex perpendicular to the opposite side.
  • Upon reviewing the diagram of triangle ABC ABC , line segment AD AD is a reference term. It appears to meet point C C in the middle, suggesting it's a median, but it also forms right angles suggesting it is an altitude.
  • Given the placement and orientation of AD AD , it is perpendicular to line BC BC (the opposite base for the median from A A ). Therefore, this line is both the median and the altitude to side BC BC .

Thus, the side to which both the median and the altitude are drawn is BC.

Therefore, the correct answer to the problem is the side BC BC , corresponding with choice Option 2: BC \text{Option 2: BC} .

Answer

BC

Exercise #3

Look at triangle ABC below.

What is the median of the triangle and to which side is it drawn?

AAABBBCCCDDDEEE

Step-by-Step Solution

A median of a triangle is a line segment that connects a vertex to the midpoint of the opposite side. In triangle ABC \triangle ABC , we need to identify such a median from the diagram provided.

Step 1: Observe the diagram to identify the midpoint of each side.

Step 2: It is given that point E E is located on side AC AC . If E E is the midpoint of AC AC , then any line from a vertex to point E E would be a median.

Step 3: Check line segment BE BE . This line runs from vertex B B to point E E .

Step 4: Since E E is labeled as the midpoint of AC AC , line BE BE is the median of ABC \triangle ABC drawn to side AC AC .

Therefore, the median of the triangle is BE BE for AC AC .

Answer

BE for AC

Exercise #4

Look at triangle ABC below.

Which is the median?

αααAAABBBCCCDDDEEE

Step-by-Step Solution

To solve this problem, we must identify which line segment in triangle ABC is the median.

First, review the definition: a median in a triangle connects a vertex to the midpoint of the opposite side. Now, in triangle ABC:

  • Point A represents the vertex.
  • Point E lies on line segment AB.
  • Line segment EC needs to be checked to see if it connects vertex E to point C.

From the diagram, it appears that E is indeed the midpoint of side AB. Thus, line segment EC connects vertex C to this midpoint.

This fits the definition of a median, verifying that EC is the median line segment in triangle ABC.

Therefore, the solution to the problem is: EC \text{EC} .

Answer

EC

Exercise #5

Look at the triangle ABC below.

AD=12AB AD=\frac{1}{2}AB

BE=12EC BE=\frac{1}{2}EC

What is the median in the triangle?

AAABBBCCCEEEDDD

Step-by-Step Solution

A median in a triangle is a line segment connecting a vertex to the midpoint of the opposite side. Here, we need to find such a segment in triangle ABC \triangle ABC .

Let's analyze the given conditions:

  • AD=12AB AD = \frac{1}{2}AB : Point D D is the midpoint of AB AB .
  • BE=12EC BE = \frac{1}{2}EC : Point E E is the midpoint of EC EC .

Given that D D is the midpoint of AB AB , if we consider the line segment DC DC , it starts from vertex D D and ends at C C , passing through the midpoint of AB AB (which is D D ), fulfilling the condition for a median.

Therefore, the line segment DC DC is the median from vertex A A to side BC BC .

In summary, the correct answer is the segment DC DC .

Answer

DC

Start practice
Related Subjects