Question

Find the area of a rectangle whose length is 20cm and diagonal is 25cm.

Answer 1

diagonal = 25cm
lenght = 20cm
then by PGT,
Breadth = √(25)²-(20)²
              = √625-400
               = √225
               = 15 cm
area of rectangle = lb
                            = 20*15
                            = 300 cm² 

Answer 2

Answer:

Step-by-step explanation:

Rectangle has 4 sides 4 angles that 2 opposite sides are equal and each and every angle is a right angle.

The formula of area of a rectancle= length x breadth=LxB

In given question L =20 cm

B= ?

Diagonal, D = 25

According pythagorean theorem

$D^{2} =L^{2} +B^{2}$

$25^{2} =20^{2} +B^{2}$

$B^{2} =25^{2} -20^{2}$

$B^{2} =625-400$

$B^{2} =225\\B=\sqrt{225} \\B=15$

So area of rectangle = LxB = 20 x15

$=300 cm^{2}$