Question

The equal sides of the isosceles triangle are 12cm and the perimeter is 30 cm then find third side of triangle​

Answer 1

Question :-

The equal sides of the isosceles triangle are 12cm and the perimeter is 30 cm then find third side of triangle.

Answer :-

Let third side be x

We know that,

Sum of all sides of a triangle is perimeter.

12 + 12 + x = 30

24 + x = 30

x = 30 - 24

x = 6

Therfore,Third side of a triangle is 6 cm.

Hope this helps!

Answer 2

$\bold{Given}\begin{cases}\sf \: Two \: sides \: of \: a \: triangle \: are \: \bold{12cm} \: and \: \bold{12cm}. \\ \\ \sf \: Perimeter \: of \: the \: triangle \: is \: \bold{30cm}. \end{cases}$

We've to find the third side of the triangle.

______________________

As we know that :

$\underline{\boxed{\sf\purple{\bigstar \: perimeter \: of \: a \: rectangle \: = sum \: of \: all \: sides}}}$

Here

First side of the triangle (a) = 12cm

Second side of the triangle (b) = 12cm

Perimeter of the triangle (P) = 30cm

Put the values -

$\tt:\implies \: p \: = a + b + c \\ \\ \\ \tt:\implies \: 30 = 12 + 12 + c \\ \\ \\ \tt:\implies \: 30 = 24 + c \\ \\ \\ \tt:\implies \: c = 30 - 24 \\ \\ \\ \tt:\implies \: c = \underline{\boxed{\sf\purple{6cm}}}\bigstar \\ \\ \\ \\ \sf\therefore{\underline{Hence, \: the \: third \: side \: of \: the \: triangle \: \bold{6 cm}.}}$