. The difference between the semi perimeter and the sides of ∆ABC are 8 cm, 7 cm and
5 cm respectively. Find its semi perimeter.

21

Step-by-step explanation:

I'll represent semi perimeter as s

What we know:

s-A=8

s-B=7

s-C=6

A+B+C=2s

we can substitute all the sides in the equation

s-A=8

s-8-A=0

s-8=A

Do this for B and C

A+B+C=2s

(s-8)+(s-7)+(s-6)=2s

3s-21=2s

-21=-s

s=21

36 girls

step-by-step explanation:

the 48 boys is 4 parts of the ratio

divide 48 by 4 to obtain one part of the ratio

= 12 ← 1 part of the ratio

3 parts = 3 × 12 = 36 ← number of girls

hello i am doing good for you that it's summer in your country or state ; )

btw in my country we just have sun and rain as (because i live in the caribbean lol)

also, thx a lot for the points : )