Question

Hi guys please help me in this question
Book: M.L. Aggarwal
Class: 9
Question:1
The length and breadth of a rectangle are 12 cm and 9cm respectively. Find the height of a triangle whose base is 9 cm and whose area is one third that of rectangle.
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Answer 1

Solution :-

• Area of rectangle = L × B

= 12 × 9 = 108cm²

• Area of triangle = 1/3 of area of rectangle

= 1/3 × 108 = 36cm²

• Area of triangle = 1/2 × B × H

36 = 1/2 × 9 × H

height = 8 cm

hope it helps you !!!

Answer 2

Solution:-

Area of rectangle = Length × Breadth

= 12 cm × 9cm

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \: \: \: 108 {cm}^{2}$

Area of triangle is 1/3 of area of rectangle

$= \frac{1}{3} \times 108 {cm}^{2}$

$= 36 {cm}^{2}$

Now find height of triangle

$area \: of \: triangle \: = \frac{1}{2} \times b \times h$

$\: \: \: \: \: 36 {cm}^{2} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \frac{1}{2} \times 9cm \times h$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \frac{36 {cm}^{2} \times 2 }{9cm} \: \: \: \: \: \: \: = h$

$\: \: \: \: \: 4cm \times 2 \: \: \: \: \: \: \: \: \: \: \: \: \: = h$

$\: \: \: \: \: \: \: 8cm \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = h$

Height of triangle is 8cm.

Hope this helps you.

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