Question

The area (A) of a rectangle varies jointly as the length (l) and the width (w), and whose A = 60 sq. cm when l = 4 cm and w = 3 cm. What is the area of rectangle if the length is 6 cm and whose width is 3 cm? ​

Answer 1

Answer:

The area is 90 sq. cm

Step-by-step explanation:

Given

The variation can be represented as:

$A\ \alpha\ l * w$

Area = 60, when l = 4 and w = 3

Required

Find Area, when l = 6 and w = 3

Represent the variation as an equation

$A = k(l * w)$

Where k is the constant of variation.

Substitute 60 for A, 4 for l and 3 for w

$60 = k * (4 * 3)$

$60 = k * 12$

Make k the subject

$\frac{60}{12} = k$

$5=k$

$k=5$

To get the value of Area when l = 6 and w = 3.

Substitute 5 for k, 6 for l and 3 for w in $A = k(l * w)$

$A = 5 * 6 * 3$

$A = 90$

The area is 90 sq. cm