Mathematics

The angles of a pentagon are x°, 2x°, (x + 60)°, (x + 10)°, (x -10)°. Find…

The angles of a pentagon are x°, 2x°, (x + 60)°, (x + 10)°, (x -10)°. Find the value of x.

  • A.
    40
  • B.
    60
  • C.
    75
  • D.
    80
  • E.
    90
Correct Answer: Option D
Explanation

Sum of ∠s in a pentagon = (n – 2)180 = 540°
x° + 2x° + x° + 60° + x° + 10° + x° – 10° = 540°
6x° + 60° = 540°; x = 80°