Answer:
Choice a : x= 102 degrees because 180°- (63°+39° ) = 78° and 180° - 78° = 102°
Explanation:
Two angles are given as 63° and 39°
To find the third angle we subtract the other two angles from 180°
180°- 63°-39° gives 78°as the third inner angle .
The third angle and the outer angle x lie on the straight line making a total of 180°.
To find x we again subtract the inner angle 78° from 180°.
This gives the value of x to be 102°
180°- 78°=102°
Choice a is the best option.