If one angle of a triangle is 50° and difference between the remaining two angles is 30°, then the value of smaller angle is :

If the difference between the circumference and radius of a circle is 37 cm, then the area of the circle is

If the difference between the interior and exterior angles of a regular polygon is 144°, then what is the number of sides of the polygon ?

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)?

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 ?

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