Question: ABC and XYZ are two similar triangles with $ \angle C=\angle Z, $ whose areas are respectively $ 32cm^{2} $ and $ 60.5cm^{2}. $ If $ XY=7.7cm, $ then what is AB equal to?
Options:
A) $ 5.6cm $
B) $ 5.8cm $
C) $ 6.0cm $
D) $ 6.2cm $
Show Answer
Answer:
Correct Answer: A
Solution:
- For similar triangles, ratio of areas is equal to the ratio of the squares of any two corresponding sides.
Here, $ \frac{areaof\Delta ABC}{areaof\Delta XYZ}=\frac{AB^{2}}{XY^{2}} $
$ \Rightarrow $ $ \frac{32}{60.5}=\frac{AB^{2}}{{{(7.7)}^{2}}} $
$ \Rightarrow $ $ \frac{32\times 59.29}{60.5}=AB^{2} $
$ \Rightarrow $ $ 31.36=AB^{2} $
$ \therefore $ $ AB=\sqrt{31.36}=5.6cm $