ABCD is a quadrilateral in which measures of angle D and angle C are 60 degree and 100 degree respec...........

Quantitative Aptitiude (CLAT) Mensuration

ABCD is a quadrilateral in which measures of angle D and angle C are 60 degree, and 100 degree respectively. If the internal bisectors of angle A and angle B meet at P, then measure of angle APB is

80⁰

90⁰

100⁰

110⁰

Explanation:

Suppose the point p lies on the DC.
now A+B+C+D=360 we know the Angles C and D so A+B=200 ....
In triangle APB angle PAB = A/2 and PBC = B/2 therefore angle PAB + PBA + P =180 this imply
A/2 + B/2 + P = 180
(A + B)/2 + P = 180
P = 180 -100
P=80