Question

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

• A.
  $1840c{m}^2$
• B.
  $1680c{m}^2$
• C.
  $1480c{m}^2$
• D.
  $1844c{m}^2$

Answer 1

The correct option is B

$1680c{m}^2$
$a=25cmb=25cmc=14cms=\frac{25+25+14}{2}=\frac{64}{2}=32cm\therefore \text{Area of the triangle}=\sqrt{\left(s\right(s-a\left)\right(s-b\left)\right(s-c\left)\right)}\therefore \text{Area of 1 triangular piece}=\sqrt{32\times 7\times 7\times 18}=168c{m}^2\therefore \text{Total area of paper needed to make the head fan}=(168\times 10)c{m}^2=1680c{m}^2$

So, option b is correct.