Question

Find the value of a and b.? The polygons are similar, but not necessarily drawn to scale.

Answer 1

See below

Explanation:

If the polygons are similar, then the sides must be proportional
`18/30=15/(3b+1)`
`54b+18=450`
`54b=432`
`b=8`

`18/30=(2a-5)/25`
`60a-150=450`
`60a=600`
`a=10`