You may also like

Areas and Ratios

Do you have enough information to work out the area of the shaded quadrilateral?

Biggest Bendy

Four rods are hinged at their ends to form a quadrilateral. How can you maximise its area?

So Big

One side of a triangle is divided into segments of length a and b by the inscribed circle, with radius r. Prove that the area is: abr(a+b)/ab-r^2

Diagonals for Area

Age 16 to 18
Challenge Level

Prove that the area of a quadrilateral is given by half the product of the lengths of the diagonals multiplied by the sine of the angle between the diagonals.