In the adjacent figure, the bisectors of and meet in a point P. D

If =100° and = 60°, find the measure of.

As we know that, Sum of all four angles of quadrilateral is 360^o.

A + B + C + D = 360°

A + B + 100° + 60° = 360°

A + B = 360° - 160°

= 200°

Now, according to question bisector of and meet in a point P and forms the triangle

PAB.

So,

1/2 A + 1/2 B = 200°/2

= 100°

As we know that, sum of all angles of triangle is 180°.

1/2 A + 1/2 B + APB = 180°

100° + APB = 180°

APB = 180° - 100°

= 80°

So, APB = 80°