Question

In a quadrilateral three angles are 55°,60°,105°.The 4th angle is​

Answer 1

Let the 4th angle be x
Then,
55+60+105+x = 360
220+x = 360
x = 360-220
x = 140

Hence , the 4th angle is 140.

Answer 2

Answer:

The sum of all interior angles of a quadrilateral is 360°

1st angle = 55°

2nd angle = 60°

3rd angle = 105°

4th angle = x

Sum = 360°

55° + 60° + 105° + x = 360°

55° + 165° + x = 360°

220° + x = 360°

x = 360° - 220°

x = 140°

Hence the 4th angles of the quadrilateral is 140°