Answer:
The area of the second triangle is 242 cm²
Explanation:
In the similar triangles
- The ratio between their perimeters equals the ratio between their corresponding sides
- The ratio between their areas equals square the ratio between their corresponding sides
∵ The length of a pair of corresponding sides of two similar ∆'s are
3 cm and 11 cm
→ Find the ratio of the corresponding sides
∴ The ratio of their corresponding sides =

∵ The area of the first ∆ is 18 cm²
→ Use the second rule above
∵
=

∵ A1 = 18 cm²
→ Substitute it in the ratio above
∴
=

→ By using the cross multiplication
∵ A2 × 9 = 18 × 121
∴ 9A2 = 2178
→ Divide both sides by 9
∴ A2 = 242 cm²
∴ The area of the second triangle is 242 cm²