Or search by topic
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.
Do you have enough information to work out the area of the shaded quadrilateral?
Four rods are hinged at their ends to form a quadrilateral. How can you maximise its area?
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