∵ ∠P + ∠Q + ∠R + ∠S = 360°
∴ 100° + ∠Q + 100° + 75° = 360°
⇒∠Q + 275° = 360°
⇒ ∠Q = 360° − 275°
∴ ∠Q = 85°
Steps of Construction :
(i) Draw a line segment PQ = 5 cm.
(ii) At Q, draw a ray QX making an angle of 85° and cut off QR = 6.5 cm.
(iii) At R, draw a ray making an angle of 100° and at, P, another ray making an angle of 100° which intersect each other at S.
then ∠S = 75°.
PQRS is the required quadrilateral.
