Area of triangle
1)Find the area of an acute triangle with a base of 15 cm and a height of 4 cm. 

2)A triangle and a parallelogram have the same base and the same area. If the sides of the triangle are 15 cm, 14 cm and 13 cm, and the parallelogram stands on the base 15 cm, find the height of the parallelogram 

3)How much area of a triangle will increase if its each side is doubled. Calculate the percentage increase 

4)If each side of the triangles is doubled ,Area of the triangle will become? 

5)Find out the area of a right angle triangle which has base as 21 cm and perpendicular as 42 cm.