Test your understanding of the triangle angle rule.
Try to answer the questions before checking the answers at the bottom of the page.
Question 1
Two angles of a triangle are 40° and 50°.
Find the third angle.
A) 80°
B) 90°
C) 100°
Question 2
Angles of a triangle are 90°, 30°, and x.
Find x.
A) 40°
B) 50°
C) 60°
Question 3
Two angles of a triangle are equal and the third angle is 40°.
Find the value of each equal angle.
A) 60°
B) 70°
C) 80°
Question 4
Angles of a triangle are x, x, x.
Find x.
A) 60°
B) 90°
C) 120°
Question 5
Angles of a triangle are 70°, 80°, and x.
Find x.
A) 20°
B) 30°
C) 40°
Answers
1️⃣ B – 90°
2️⃣ C – 60°
3️⃣ B – 70°
4️⃣ A – 60°
5️⃣ B – 30°
Practice
- More Examples
- Take the Quiz
Continue Learning
- Types of Triangles
- Triangles (Basics)
- Sum of Angles of a Triangle is 180° (Proof)
- Find the Missing Angle of a Triangle
- Sum of Exterior Angles of a Triangle (Proof)
- Exterior Angle Theorem of a Triangle
- Two Exterior Angles at a Vertex are Equal (Proof)
- Two Exterior Angles are Equal at a Vertex (Quick Proof)