HERON'S FORMULA - Math with JM - home

JM-2012-9-WES10-Herons Formula
HERON’S FORMULA
Type: Understanding ( Marks – 2 each)
1. Find area of a right triangle with one of the sides and the hypotenuse as
3 and 5 cms respectively.
2. Find area of an equilateral triangle with a side 10cm long.
3. Express the altitude of an Isosceles triangle with two equal sides ‘a’ and
base ‘b’ in terms of a and b.
4. Find the area of an isosceles triangle whose base is 4cm and the length
of one of its equal sides is 6cm.
5. Using Heron’s Formula evaluate the area of the triangle whose Perimeter
is 180cm and two of its sides are 80cm and 18cm.
Type: Application of Concepts ( Marks – 4 each)
Higher Order Thinking
6. Perimeter of an isosceles triangle is 14cm and the ratio of lateral side to
the base is 5:4. Find the area of the triangle.

7. In the given figure AC=14cm and radius of incircle of ∆ABC is 4cm, given
AF=AE=6cm and CD=CF=8cm, find AB and BC.
8. Find the cost of revamping the damaged area(shaded portion) of the
sports ground if the cost of revamping is Rs. 2500 per cm 2 (Figure not to scale)
9. Perimeter of an isosceles triangle is 14 cm and the ratio of lateral side to
the base is 5:4. Find the area of the triangle.
10. Dimensions of a rectangle ABCD are 51cm x 25 cm. A trapezium PQCD
with its parallel sides, QC and PD in the ratio 9:8 is cutoff from the
rectangle. If the area of trapezium PQCD is 5/6 th of the area of rectangle,
find the lengths QC and PD.