Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Geometry

Question:

ABCD is a cyclic quadrilateral which sides AD and BC are produced to meet at P, and sides DC and AB meet at Q when produced. If $\angle A = 60^\circ$ and $\angle ABC = 72^\circ$, then $\angle PDC - \angle DPC =$

Options:

24°

30°

36°

40°

Correct Answer:

24°

Explanation:

In Triangle APB,

∠A + ∠B + ∠P = 180º

60º + 72º + ∠P = 180º

∠P = 48º

In a cyclic quadrilateral,

∠BAD + ∠BCD = 180º

∠BCD = 180º - 60º = 120º

&

∠ABC + ∠ADC = 180º

∠ADC = 180º - 72º = 108º 

Now,

∠ADC + ∠PDC = 180º

∠PDC = 180º - 108º  = 72º 

According to question ,

∠PDC - ∠DPC = 72º  - 48º

= 24º