In the figure, ∠AOB=90∘,AC=BC,OA=12 cm and OC=6.5cm. Find the area of △AOB
In △AOB,∠AOB=90∘
C is a point on AB such that AC = BC join OC
Since C is the mid point of hypotenuse of right △AOB
∴AC=CB=OC=6.5cm[Since mid-point of the hypotenuse of a right triangle is equidistant from the vertices.]∴AB=6.5+6.5=13cmNow in right △AOBAB2=AO2+OB2⇒(13)2=(12)2+OB2⇒169=144+OB2⇒OB2=169−144=25=(5)2∴OB=5cmNow area of △AOB=12Base×Altitude=12×OB×AO=12×5×12=30cm2