Question

A quadrilateral has three acute angles each measuring 85 ○ .Find the measure of forth angle.

Answer 1

the sum of Angles of a quadrilateral is 360°
angle1+angle2+angle3+angle4=360°
(three angle of this quadrilateral measure 85°)
85+85+85+angle4=360
255+angle4=360
angle4=360-255
angle4=105°

Answer 2

sum of three angles = 85+85+85=255                                                                  sum of angles of quadrilateral = 360
  360 - 255 = 105
  fourth angle measures 105