Question

In a triangle , the length of the first side is 5 cm less than the length of the second side . The length of the third side is 7 cm more than the length of the first side if the first side is of length is 18 cm , then what is the semiperimeter of the triangle?​

Answer 1

Given :

• In a triangle,

First side → The length of the first side is 5 cm less than the length of the second side.

Third side → The length of the third side is 7 cm more than the length of the first side.

Length of the first side → 18cm

To find :

• Semiperimeter of the triangle

Solution :

• Length of the first side → 18cm

First side → The length of the first side is 5 cm less than the length of the second side.

• Consider the second side be x

→ Second side = first side - 5

→ x = 18 - 5

→ x = 13

•°• Length of the second side = 13 cm

Third side → The length of the third side is 7 cm more than the length of the first side.

• Consider the third side be y

→ Third side = 7 + first side

→ y = 7 + 18

→ y = 25

•°• Length of the third side = 25cm

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So, semiperimeter of triangle is given as the sum of all the sides of a triangle divided by 2

• a + b + c/2

★ First side = a = 18cm

★ Second side = b = 13cm

★ Third side = c = 25cm

• Semiperimeter of triangle

→ a + b + c/2

→ 18 + 13 + 25/2

→ 56/2

→ 28cm

•°• The semiperimeter of trianlge is 28cm

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Answer 2

Given :-

A triangle the length of the first side is 5 cm less than the length of the second side . The length of the third side is 7 cm more than the length of the first side if the first side is of length is 18 cm ,

To Find :-

Semi-perimeter

Solution :-

Let the second side be 'b' and third side be 'c'

When the second side is 5 cm less than other

b = 18 - 5

b = 13 cm

Now

c = 18 + 7

c = 25

Sides of triangles are 25 cm,13 cm,18 cm

Now

Semi perimeter = a + b + c/2

S = 18 + 13 + 25/2

S = 18 + 38/2

S = 56/2

S = 28 cm

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