Question

the size of a triangle are in the ratio 3:5:7 and its perimeter is 45 cm what are the length of the sides​

Answer 1

9cm (putting the value of x )

second side was = 5x =  5 x 3 = 15 cm

third side was = 7x  =  7 x 3  =21cm Answer

sides are as follows

1. first side = 9
2. second  side = 15
3. third side=21

Step-by-step explanation:

let the common factor be "X"

so the ratio of sides will be  

1. 3x
2. 5x
3. 7x

now, add all the ratio of the sides,

3x+5x+7x  =  15x

Now, according to the question  

perimeter is 45 cm =

perimeter of triangle =  a+b+c  =15x

45cm                        =15x

x=3cm  ANSWER

but if you are asked to find the measure of the sides then  

first side wass   =  3x = 3 x 3 = 9 cm  (by putting the same value of x )

second  side was  =  5x  = 5  x 3 =15 cm

third sidde was  = 7x =  7  x  3  =  21  cm