Answer:
a =9
b= 28
Step-by-step explanation:
The parts of the ratio must be equal
5:7:a = 20:b:36
How do we get from 5 to 20
We multiply by 4
So multiply the first by 4
5*4:7*4:a*4 = 20:b:36
Ratio 1
5*4 =20 true
Ratio 2
7*4 =b
28 = b
Ratio 3
4a = 36
Divide by 4
4a/4 = 36/4
a = 9
