**Find the area of a triangle two sides of which are 18 cm and 10 cm and the perimeter is 42 cm.**

**Solution:**

Length of first side of triangle **cm**

Length of second side of triangle **cm**

Perimeter of triangle **cm**

Length of third side of triangle =c=Perimeter of triangle-a-b **cm**

Semi-perimeter of triangle **cm**

Using** Heron's formula** to find area of triangle, we get

Area of triangle