The diagonal of a quadrilateral is 20 cm in length and the lengths of perpendiculars on it from the opposite vertices are 8.5 cm and 11.5 cm. The area of the quadrilateral is


Given : A quadrilateral


Diagonal AC = 20 cm


Perpendiculars to diagonal AC are: BL = 11.5 cm and DM = 8.5 cm


Now,


Area (quad. ABCD) = area (ABC) + area (ADC)


Area of triangle = × (base) × (height).


Therefore


Area of quad ABCD = × (AC) × (BL) + × (AC) × (DM)


= × (20) × (11.5) + × (20) × (8.5) = 115 + 85 = 200 cm2


Therefore area of the quadrilateral ABCD is 200 cm2.

9