The base of a triangle is 15 dm and its height is 12 dm. The height of another triangle of double the area and the base of which is 20 dm, is given by

The sides of a triangle are 5 cm, 12 cm and 13 cm. then its area is

If the sides of a triangle are doubled, then its area

The length of a given rectangle is increased by 20% and the breadth is decreased by 20%, then the area

A triangle has side lengths x cm, x + 31 cm and x + 26 cm. If its area is 126 square cm, then what is the value of x ?

If a, b and c are the sides of a right-angled triangle, where a > b > c, then what is the value of the expression (a + b + c) (a + b - c) (a - b + c) (a - b - c)?