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

Is the triangle in the drawing an acute-angled triangle?

Examples with solutions for Types of Triangles

Step-by-step solutions included
Exercise #1

Is the triangle in the drawing a right triangle?

Step-by-Step Solution

Due to the presence of the 90 degree angle symbol we can determine that this is indeed a right-angled triangle.

Answer:

Yes

Exercise #2

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 #3

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 #4

Fill in the blanks:

In an isosceles triangle, the angle between two ___ is called the "___ angle".

Step-by-Step Solution

In order to solve this problem, we need to understand the basic properties of an isosceles triangle.

An isosceles triangle has two sides that are equal in length, often referred to as the "legs" of the triangle. The angle formed between these two equal sides, which are sometimes referred to as the "sides", is called the "vertex angle" or sometimes more colloquially as the "main angle".

When considering the vocabulary of the given multiple-choice answers, choice 2: sides,mainsides, main accurately fills the blanks, as the angle formed between the two equal sides can indeed be referred to as the "main angle".

Therefore, the correct answer to the problem is: sides,mainsides, main.

Answer:

sides, main

Exercise #5

In an isosceles triangle, the angle between ? and ? is the "base angle".

Step-by-Step Solution

An isosceles triangle is one that has at least two sides of equal length. The angles opposite these two sides are known as the "base angles."
The side that is not equal to the other two is referred to as the "base" of the triangle. Thus, the "base angles" are the angles between each of the sides that are equal in length and the base.
Therefore, when we specify the angle in terms of its location or position, it is the angle between a "side" and the "base." This leads to the conclusion that the angle between the side and the base is the "base angle."

Therefore, the correct choice is Side, base.

Answer:

Side, base.

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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