3 Views

Question : The altitude drawn to the base of an isosceles triangle is 8 cm and its perimeter is 64 cm. The area (in cm2) of the triangle is:

Option 1: 240

Option 2: 180

Option 3: 360

Option 4: 120


Team Careers360 18th Jan, 2024
Answer (1)
Team Careers360 21st Jan, 2024

Correct Answer: 120


Solution :
Let the base of the isosceles triangle as $b\operatorname{ cm }$ and each of the equal sides as $a\operatorname{ cm }$.
The altitude drawn to the base = $8\operatorname{ cm }$
The perimeter of the isosceles triangle = $64\operatorname{ cm }$
In an isosceles triangle, the altitude bisects the base, dividing it into two equal parts.
Let each part as $\frac{b}{2}$.
We can use the Pythagorean theorem,
$⇒a = \sqrt{(\frac{b}{2})^2 + 8^2}$ ____(i)
Given that the perimeter of the triangle is $64\operatorname{ cm }$.
$⇒2a + b = 64$ ____(ii)
From equation (i) and equation (ii),
$⇒2\sqrt{(\frac{b}{2})^2 + 8^2} + b = 64$
$⇒\sqrt{ b^2 + 256}=64-b$
$⇒b^2 + 256=4096-128b+b^2$
$⇒128b=3840$
$⇒b = 30\operatorname{ cm }$
From equation (ii),
$⇒a = 17\operatorname{ cm }$.
The area of the triangle $=\frac{1}{2}bh=\frac{1}{2} \times 30 \times 8 = 120\operatorname{ cm^2 }$
Hence, the correct answer is 120.

How to crack SSC CHSL

Candidates can download this e-book to give a boost to thier preparation.

Download Now

Know More About

Related Questions

TOEFL ® Registrations 2024
Apply
Accepted by more than 11,000 universities in over 150 countries worldwide
Manipal Online M.Com Admissions
Apply
Apply for Online M.Com from Manipal University
View All Application Forms

Download the Careers360 App on your Android phone

Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile

150M+ Students
30,000+ Colleges
500+ Exams
1500+ E-books