Answer:
The new length is 39 cm
Step-by-step explanation:
We will use the ratio method to solve the question
∵ A length, originally 9cm, is increased
∴ The original length = 9 cm
∵ The ratio of the new length to the old length is 13 : 3
→ That means the ratio is ⇒ New : Original is 13 : 3
∴ The ratio New : Original = 13 : 3
→ By using the ratio method
→ New : Original
→ 13 : 3
→ x : 9
→ By using cross multiplication
∵ x × 3 = 13 × 9
∴ 3x = 117
→ Divide both sides by 3
∵ [tex]\frac{3x}{3}[/tex] = [tex]\frac{117}{3}[/tex]
∴ x = 39
∵ x represents the new length
∵ x = 39
∴ The new length is 39 cm
