Question

The semiperimeter of a triangle is 30 cm and its sides are in the ratio 3 : 4 : 5. What is its perimeter?​

Answer 1

Semi-perimeter = 60 cm

Perimeter = 2 × 60 cm

= 120 cm

Let the sides of a triangle be 3x , 4x and 5x respectively.

Perimeter of triangle = 3x + 4x + 5x

=> 120 cm = 12x

Therefore, x = 120÷12

= 10 cm

1st Side = 3x

= 3 × 10 cm

= 30 cm

2nd Side = 4x

= 4 × 10 cm

= 40 cm

3rd Side = 5x

= 5 × 10 cm

= 50 cm

Answer 2

Answer:

60 is the perimeter

Step-by-step explanation:

Let the required number be ' x '

( 3x + 4x + 5x ) / 2 = 30

12x = 30 × 2

12x = 60

x = 60/12

x = 5

So,

3x = 3 × 5 = 15

4x = 4 × 5 = 20

5x = 5 × 5 = 25

Now, perimeter of triangle = sum of all sides

So , ( 15 + 20 + 25 ) = 60 is your answer.

HOPE YOU UNDERSTAND AND THIS MAY HELP YOU