One angle of the triangle is 3 times a second angle and third angle is 20…
2025
One angle of the triangle is 3 times a second angle and third angle is 20 degree more than the second angle. Then the second angle is ?
- A.
12 degree
- B.
35 degree
- C.
32 degree
- D.
25 degree
Attempted by 4 students.
Show answer & explanation
Correct answer: C
Solution:
Let the second angle be x.
Then the first angle is 3x and the third angle is x + 20.
Use the triangle angle-sum: 3x + x + (x + 20) = 180.
Simplify: 5x + 20 = 180 ⇒ 5x = 160 ⇒ x = 32°.
Check: the angles are 3×32 = 96°, 32°, and 32 + 20 = 52°; 96 + 32 + 52 = 180°, so the answer is consistent.