Examples with solutions for Parts of a Triangle: Using properties of the median

Exercise #1

AD is the median and the height of triangle ABC.

AD = 8

Calculate the area of the triangle.

AAABBBCCCDDD58

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Identify the given information (height) and determine the relationship with the triangle's base.
  • Step 2: Apply the area formula for triangles using height and base.
  • Step 3: Calculate the area and verify it against plausible solution choices.

Now, let's work through each step:
Step 1: We know that AD=8 AD = 8 is both the median and height. As a midpoint implies BD=DC=BC2 BD = DC = \frac{BC}{2} , set BC=10 BC = 10 ensuring appropriate arithmetic association.
Step 2: Applying the area formula Area=12×BC×AD \text{Area} = \frac{1}{2} \times BC \times AD , substitute BC=10 BC = 10 and AD=8 AD = 8 .
Step 3: Plugging in our values, we get Area=12×10×8=40 \text{Area} = \frac{1}{2} \times 10 \times 8 = 40 .

Therefore, the correct area of triangle ABC \triangle ABC is 40 40 , confirming that choice 2 2 is correct.

Answer

40

Exercise #2

AD is the median and the height of triangle ABC.

AD = 9

Calculate the area of triangle ABC.

AAABBBCCCDDD6.59

Video Solution

Step-by-Step Solution

To solve the problem of finding the area of triangle ABCABC, we follow these steps:

  • Step 1: Recognize that ADAD is a median and also the height, hence it bisects BCBC into two equal lengths.
  • Step 2: Given BD=DC=6.5BD = DC = 6.5, determine BC=2×6.5=13BC = 2 \times 6.5 = 13.
  • Step 3: Use the area formula for triangles, Area=12×base×height\text{Area} = \frac{1}{2} \times \text{base} \times \text{height}.
  • Step 4: Substitute the known values: Area=12×13×9=58.5\text{Area} = \frac{1}{2} \times 13 \times 9 = 58.5.

The area of triangle ABCABC is, therefore, 58.5 58.5 .

Answer

58.5

Exercise #3

Given AD median.

Given BC=AC.

Calculate BC+AC.

AAABBBCCCDDD6

Video Solution

Answer

24