Answer:
The value of x in centimeters is 22.5 cm
Explanation:
The corresponding sides of the similar triangles are proportion which means have equal ratios
∵ Δ ABC is similar to Δ FGH
∵ AB and FG are corresponding sides
∵ BC and GH are corresponding sides
∵ AC and FH are corresponding sides
→ That means the ratios between them are equal
∴
=
=

∵ AB = 6 cm and FG = 15 cm
∵ BC = 5 cm and GH = 12.5 cm
∵ AC = 9 cm and FH = x
→ Substitute them in the rule above to find x
∴
=
=

→ By using cross multiplication with the 1st and 3rd ratios
∵ 6 × x = 15 × 9
∴ 6x = 135
→ Divide both sides by 6 to find x
∵
=

∴ x = 22.5 cm
∴ The value of x in centimeters is 22.5 cm