Question

The length and breadth of a rectangle are in the ratio 3 : 4 If the diagonal measures 15 cm , find the
perimeter of the rectangle. ​

Answer 1

Answer:

Perimeter is 42cm. Please mark me as brainliest.

Step-by-step explanation:

Let the Length be 3x and breadth be 4x (From ratio)

Pythagoras theorem in rectangle:

$Diagonal^2 = Length^2 + Breadth^2\\(15cm)^2 = (3x)^2 + (4x)^2\\225cm^2 = 9x^2 + 16x^2\\25x^2 = 225cm^2\\x^2 = 9cm^2\\x = \sqrt{9cm^2} \\x = 3cm$

Length = 3x = 3 x 3cm = 9cm

Breadth = 4x = 4 x 3cm = 12cm

Perimeter of rectangle = 2(l+b)

= 2(9cm+12cm)

= 2(21cm)

= 42cm