express the ratio 20cm to 15m in the form 1:n
15m=1500cm
20cm:1500cm
20:1500
1:75
The process of solving the work
If 100cm : 1m
Then 20cm :X
X(100cm)= 20cmx1m
Divide both sides by 100cm
x=2x 1m÷10
=x=0/2m
20cm =0.2m
0.2m :15m
0.2=2÷10
2÷10 ÷ 15÷1
= 2÷10 × 1÷15
=2÷150= 1÷75
*
15m=1500cm
20:1500
1:75
1 m =100cm
15m= 1500cm
20cm : 1500cm
1:75cm