Question

A rectangular piece of canvas measures 25 cm $\times$ 16 cm. A triangular piece, with base 14 cm and height 10 cm is cut off from the canvas. Find the area of the remaining piece.

• A. $400c{m}^2$
• B. $120c{m}^2$
• C. $140c{m}^2$
• D. $330c{m}^2$

Answer 1

The correct option is D $330c{m}^2$

Let $ABCD$ is a rectangular piece of canvas.
$△LBM$ is the triangular piece to be cut off.
Require area $=$ area of rectangular $ABCD-$ area of $△LBM$

We know that, the area of a rectangle is $l\times b$

Also, area of a triangle is $\frac{1}{2}\times b\times h$

For rectangle, we have $l=25,b=16$

and for the triangle, we have $b=14,h=10$.

$\therefore$ Required area $=25\times 16-(\frac{1}{2}\times 14\times 10)$

$\Rightarrow 400-70=330c{m}^2$.

Hence, the required area is $330c{m}^2$