Answer:
22.5 cm
Step-by-step explanation:
Step 1: Identify the similar sides ( from ABC and FGH )
ABC to FGH ; ABC to FGH ; ABC to FGH
AB is similar to FG
BC is similar to GH
AC is similar to FH
Step 2: Find ratio between two triangles:
Because sides AB and FG are similar, we want to find the ratio between them so we can find the unknown side.
AB = 6 ; FG = 15 15/6 = 2.5
This ratio is consistent with BC to GH ( 12.5/5 = 2.5 too )
Step 3: Use ratio to find unknown side:
The side similar to our unknown side is AC ( from the fact that ABC to FGH ),
So if we multiply AC by the ratio, 2.5, we get our unknown side of 22.5