Q12 of 50 Page 12

Find the area of the blades of the magnetic compass shown in Fig. 12.27. (Take = 3.32).

Let a, b and c are the sides of blade and s is


the semi-perimeter, then its area is given by:


A = where [Heron’s Formula]


= = 5.5


A=


A = = cm2


Hence, total area of both the blades = 2 × 2.49 = 4.98 cm2


More from this chapter

All 50 →
10

Find the perimeter and area of the quadrilateral ABCD in which AB = 17 cm, AD = 9 cm, CD = 12 cm, ACB = 90° and AC = 15 cm.

 11

The adjacent sides of a parallelogram ABCD measure 34 cm and 20 cm, and the diagonal AC measures 42 cm. Find the area of the parallelogram.

 13

A hand fan is made by stitching 10 equal size triangular strips of two different types of paper as shown in Fig. 12.28. The dimensions of equal strips are 25 cm, 25 cm and 14 cm. Find the area of each type of paper needed to make the hand fan.

 14

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