To solve this you just move the letters and numbers around until you get a different equation that is the same as the original equation.
You can also rule out the last two answers because they don’t have all the values.
P = pie
s=2prh can be written as s/2ph=r if we divide s by 2ph because we need to isolate r because all the answers have r isolated.
So the answer would be b s/2ph=r
Sorry that’s really badly worded and confusing, but I hope it helps.
