Question

the perimeter of a triangle is 20cm.if two of its side are 4.2 cm and 9cm respectively​

Answer 1

Answer:

let the other side be x cm

perimeter = sum of all sides

20 = 4.2 +9 + x

20 = 13.2 + x

x = 20 - 13.2

x = 6.8 cm

Answer 2

Answer:

6.8

Step-by-step explanation:

Given perimeter = 20 cm

Side a= 4.2 cm

Side b = 9 cm

Side c =?

We know that perimeter = all sum of all sides

So,

20=a+b+c

20= 4.2 + 9+ c

Therefore c= 6.8

Hope u understood this sum