SATHEE: Quantitative Aptitude Ques 2136

Quantitative Aptitude Ques 2136

Question: The area of an isosceles $ \Delta ABC $ with AB = AC and altitude AD = 3 cm is 12 sq cm. What is its perimeter?

Options:

A) 18 cm

B) 16 cm

C) 14 cm

D) 12 cm

Show Answer

Answer:

Correct Answer: A

Solution:

Let $ AB=CA=acm $ and base = b cm Now, area of the
$ \Delta ABC=\frac{1}{2}\times b\times h $

$ \Rightarrow $ $ 12=\frac{1}{2}\times b\times 3 $

$ \therefore $ $ b=\frac{12\times 2}{3}=8cm $ Here, $ BD=CD=\frac{b}{2} $ $ =\frac{8}{2}=4cm $ In right angled $ \Delta ABD, $ by Pythagoras theorem, $ AB=\sqrt{BD^{2}+AD^{2}} $

$ \Rightarrow $ $ a=\sqrt{4^{2}+3^{2}} $

$ \Rightarrow $ $ \sqrt{16+9}=\sqrt{25}=5cm $ Now, perimeter of an isosceles triangle $ =2a+b=2\times 5+8 $ $ =10+8=18cm $

Quantitative Aptitude Ques 2135

Quantitative Aptitude Ques 2137

Quantitative Aptitude Ques 2136

Question: The area of an isosceles $ \Delta ABC $ with AB = AC and altitude AD = 3 cm is 12 sq cm. What is its perimeter?

Options:

Answer:

Solution:

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