Right Triangle Practice Problems & Exercises Online

Master right triangle concepts with interactive practice problems. Learn to identify 90-degree angles, calculate missing angles, and solve real-world applications.

📚What You'll Master in Right Triangle Practice
  • Identify right triangles by recognizing the 90-degree angle property
  • Calculate missing acute angles using the 180-degree triangle sum rule
  • Apply complementary angle relationships in right triangle problems
  • Solve step-by-step exercises involving angle measurements and calculations
  • Master real-world applications of right triangle angle properties
  • Build confidence through guided practice with immediate feedback

Understanding Types of Triangles

Complete explanation with examples

Definition of a right triangle

A right triangle is a triangle that has one right angle, meaning an angle of 90 degrees. Based on the fact that the sum of angles in any triangle is 180 degrees, we can conclude that the sum of the two remaining angles in a right triangle is 90 degrees. This means that both angles must be acute (less than 90 degrees).

Right Triangle

Detailed explanation

Practice Types of Triangles

Test your knowledge with 20 quizzes

Does the diagram show an obtuse triangle?

Examples with solutions for Types of Triangles

Step-by-step solutions included
Exercise #1

In a right triangle, the side opposite the right angle is called....?

Step-by-Step Solution

The problem requires us to identify the side of a right triangle that is opposite to its right angle.
In right triangles, one of the most crucial elements to recognize is the presence of a right angle (90 degrees).
The side that is directly across or opposite the right angle is known as the hypotenuse. It is also the longest side of a right triangle.
Therefore, when asked for the side opposite the right angle in a right triangle, the correct term is the hypotenuse.

Selection from the given choices corroborates our analysis:

  • Choice 1: Leg - In the context of right triangles, the "legs" are the two sides that form the right angle, not the side opposite to it.
  • Choice 2: Hypotenuse - This is the correct identification for the side opposite the right angle.

Therefore, the correct answer is Hypotenuse \text{Hypotenuse} .

Answer:

Hypotenuse

Exercise #2

In an isosceles triangle, what are each of the two equal sides called ?

Step-by-Step Solution

In an isosceles triangle, there are three sides: two sides of equal length and one distinct side. Our task is to identify what the equal sides are called.

To address this, let's review the basic properties of an isosceles triangle:

  • An isosceles triangle is defined as a triangle with at least two sides of equal length.
  • The side that is different in length from the other two is usually called the "base" of the triangle.
  • The two equal sides of an isosceles triangle are referred to as the "legs."

Therefore, each of the two equal sides in an isosceles triangle is called a "leg."

In our problem, we confirm that the correct terminology for these two equal sides is indeed "legs," distinguishing them from the "base," which is the unequal side. This aligns with both the typical definitions and properties of an isosceles triangle.

Thus, the equal sides in an isosceles triangle are known as legs.

Answer:

Legs

Exercise #3

In a right triangle, the two sides that form a right angle are called...?

Step-by-Step Solution

In a right triangle, there are specific terms for the sides. The two sides that form the right angle are referred to as the legs of the triangle. To differentiate, the side opposite the right angle is called the hypotenuse, which is distinct due to being the longest side. Hence, in response to the problem, the sides forming the right angle are correctly identified as Legs.

Answer:

Legs

Exercise #4

Does the diagram show an obtuse triangle?

Step-by-Step Solution

To determine if the triangle in the diagram is obtuse, we will visually assess the angles:

  • Step 1: Identify the angles in the diagram. The triangle has three angles, with one angle appearing between the horizontal base and the left slanted side.
  • Step 2: Evaluate the angle between the base and the left side. If it opens wider than a right angle, it's considered obtuse. This angle seems to be greater than 9090^\circ, indicating obtuseness.
  • Step 3: Conclude based on visual inspection. Since this key angle is greater than 9090^\circ, the triangle must be an obtuse triangle.

Therefore, the solution to the problem is Yes; the diagram does show an obtuse triangle.

Answer:

Yes

Video Solution
Exercise #5

Does the diagram show an obtuse triangle?

Step-by-Step Solution

To determine if the triangle shown in the diagram is obtuse, we proceed as follows:

  • Step 1: Identify that the diagram is indeed a triangle by observing the confluence of three edges forming a closed shape.
  • Step 2: Appreciate the geometric arrangement of the triangle, focusing on the sides' lengths and angles visually.
  • Step 3: Noticeably, the longest side of the triangle represents a noticeable tilt indicating the presence of an obtuse angle.

Based on the observation above, notably from the triangle's longest side against the base, it's clear that one angle is larger than 9090^\circ. Hence, the triangle in the diagram is indeed an obtuse triangle.

Therefore, the correct answer is Yes.

Answer:

Yes

Video Solution

Frequently Asked Questions

What makes a triangle a right triangle?

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A right triangle is defined by having exactly one right angle (90 degrees). Since all triangle angles sum to 180 degrees, the other two angles must be acute and add up to 90 degrees.

How do I find missing angles in a right triangle?

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Use the fact that angles in a triangle sum to 180°. If one angle is 90° and you know another angle, subtract both from 180° to find the third angle. For example: 180° - 90° - 45° = 45°.

Are both non-right angles in a right triangle always acute?

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Yes, both remaining angles must be acute (less than 90°). Since they must sum to 90° (because 180° - 90° = 90°), neither can be 90° or greater.

What are complementary angles in right triangles?

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In a right triangle, the two acute angles are complementary, meaning they add up to 90°. If one acute angle is 30°, the other must be 60° (30° + 60° = 90°).

Can a right triangle have two 45-degree angles?

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Yes! This creates a 45-45-90 triangle, which is a special right triangle. The angles are 45°, 45°, and 90°, and they sum to 180° as required.

How do I solve right triangle angle problems step by step?

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Follow these steps: 1) Identify the right angle (90°), 2) Write down any given angles, 3) Use the equation: missing angle = 180° - 90° - known acute angle, 4) Check that all three angles sum to 180°.

What are common mistakes when working with right triangles?

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Common errors include: forgetting that one angle must be exactly 90°, not using the triangle sum theorem correctly, and confusing complementary angles (sum to 90°) with supplementary angles (sum to 180°).

Why do right triangle problems matter in real life?

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Right triangles appear in construction, navigation, engineering, and design. Understanding angle relationships helps solve problems involving ramps, roofs, ladders, and any situation involving perpendicular measurements.

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