Question

Find the length of third side of a triangle, two sides of which are 12 cm, 18 cm and the semi-perimeter is

25 cm.​

Answer 1

Answer:

The length of the third side is 23 m.

Answer 2

Given:

• two sides of which are 12 cm, 18 cm and the semi-perimeter is 25cm

To Find:

• the length of the third side

★Understanding the question ★

➺now,let the third side be x as it's length is unknown.

we know that :

$\tt\longmapsto \: perimeter\: of \: a \: triangle = sum \: of \: all \: 3sides$

so,to find the length of the 3rd side we need to find the perimeter.!

Solution:

$\sf \underline {\bigstar \: semiperimeterter = 25cm}$

so, the whole perimeter equals

$: \tt\longrightarrow \: perimeter = 25 \times 2cm \\ \\ \\ : \tt\longrightarrow perimeter = 50cm \: \: \: \: \: \: \: \: \:$

$\underline \mathfrak\purple{hence \: the \: perimter = 50cm } ^{ \purple\bigstar}$

now, we have to find the length of 3rd side.

$: \tt\longrightarrow 12 + 18 + x = 50 cm\\ \\ \\ : \tt\longrightarrow 30 + x = 50cm \: \: \: \: \: \: \: \: \: \: \\ \\ \\ : \tt\longrightarrow xcm = 50 - 30cm \: \: \: \: \\ \\ \\ : \tt\longrightarrow xcm = 20cm \dag \: \: \: \: \: \: \: \: \: \: \: \:$

$\blue{ \underline{ \boxed{ \pink{ \mathfrak{ \therefore \: the \: lenght \: of \: 3rd \: side = 20cm}}}}}$