Question

Two sides of a triangle are 5 and 7 cm longer than the third side. If the perimeter is 21cm, find the length of each side ​

Answer 1

Let the length of the unknown side be x.

ATP:

x+5+x+7+x=21

3x+12=21

=3x=9

=x=9/3=3

Lengths are:-

x,x+5,x+7

=3,3+5,3+7

=3,8,10cm

Hope it helps mate.

Answer 2

$\huge{\sf{Question}}$

Two sides of a triangle are 5 and 7 cm longer than the third side. If the perimeter is 21cm, find the length of each side ?

$\huge{\sf{Given:-}}$

Let the third side be x

Then,

• Length of first side = (x+5)cm
• Length of second side = (x+7)cm
• Length of third side = x cm

Perimeter = 21cm

$\huge{\sf{Solution:-}}$

Perimeter of triangle = Sum of their sides

$\longrightarrow$ $\sf{(x+5+x+7+x)cm= 21cm}$

$\longrightarrow$ $\sf{(3x+12)cm = 21cm}$

$\longrightarrow$ $\sf{3x=(21-12)cm}$

$\longrightarrow$$\sf{3x=9}$

$\longrightarrow$$\sf{x= \frac{9}{3}}$

$\longrightarrow$$\sf{x=3}$

_______________________________

$\sf{\red{Therefore,the\: sides\:are:-}}$

First side = (3+5)=8cm

Second side = (3+7)=10cm

Third side = 3cm