Test your understanding of finding missing angles in a triangle.
Try to answer the questions before checking the answers at the bottom of the page.
Question 1
A triangle has angles:
\(60^\circ, x, 30^\circ\)
Find \(x\).
A) \(80^\circ\)
B) \(90^\circ\)
C) \(100^\circ\)
Question 2
A triangle has angles:
\(x, 90^\circ, 40^\circ\)
Find \(x\).
A) \(40^\circ\)
B) \(50^\circ\)
C) \(60^\circ\)
Question 3
A triangle has angles:
\(50^\circ, 100^\circ, x\)
Find \(x\).
A) \(20^\circ\)
B) \(30^\circ\)
C) \(40^\circ\)
Question 4
A triangle has angles:
\(x, 60^\circ, x\)
Find \(x\).
A) \(50^\circ\)
B) \(60^\circ\)
C) \(70^\circ\)
Question 5
A triangle has angles:
\(x, 3x, 2x\)
Find \(x\).
A) \(20^\circ\)
B) \(30^\circ\)
C) \(40^\circ\)
Question 6
A triangle has angles:
\(70^\circ,\quad 45^\circ,\quad x\)
Find \(x\).
A) \(55^\circ\)
B) \(75^\circ\)
C) \(65^\circ\)
Question 7
A triangle has angles:
\(x,\quad x,\quad 40^\circ\)
Find \(x\).
A) \(70^\circ\)
B) \(60^\circ\)
C) \(80^\circ\)
Question 8
A triangle has angles:
\(x,\quad x+20^\circ,\quad 80^\circ\)
Find \(x\).
A) \(30^\circ\)
B) \(40^\circ\)
C) \(50^\circ\)
Question 9
A triangle has angles:
\(2x,\quad 3x,\quad 5x\)
Find \(x\).
A) \(15^\circ\)
B) \(20^\circ\)
C) \(18^\circ\)
Question 10
A right triangle has one acute angle equal to \(35^\circ\).
What is the other acute angle?
A) \(55^\circ\)
B) \(45^\circ\)
C) \(65^\circ\)
Answers
- B – \(90^\circ\)
- B – \(50^\circ\)
- B – \(30^\circ\)
- B – \(60^\circ\)
- B – \(30^\circ\)
- C – \(65^\circ\)
- A – \(70^\circ\)
- B – \(40^\circ\)
- C – \(18^\circ\)
- A – \(55^\circ\)
Practice
- Take the Quiz (Current page)