Since the two figures are similar, figure
PQRS is an enlargement of figure
ABCD.
During an enlargement, each side is being multiplied by the same scale factor.
You can use any of the given sides to find the scale factor and use it to find the side of
b.
Scale factor =| Image Size of similar side |
| Object Size of similar side |
The scale factor is the same for all similar sides.
Scale factor ==== Using any of the fractions to the left of
, you can solve for the value of
b by equating it to any of the fractions at the left since they are all the same.
=Cross multiply.
b×9=15×18Divide both sides by 9
b==15×2=30cmNote: 9 divides itself once and 18, 2 times.