In the figure, find the measure of ∠MPN.
In the figure, OMPN is a quadrilateral in which ∠O=45∘,∠M=∠N=90∘
(∵PM⊥OA and PN⊥OB)
Let ∠MPN=x∘
∴∠O+∠M+∠N+∠MPN=360∘
(sum of angles of a quadrilateral)
⇒45∘+90∘+90∘+x∘=360∘⇒225∘+x∘=360∘⇒x∘=360∘−225∘⇒x=135∘∴∠MPN=135∘