129 Views

Question : The length and breadth of a rectangle are 8 cm and 6 cm, respectively. The rectangle is cut on its four vertices such that the resulting figure is a regular octagon. What is the length of the side (in cm) of the octagon?

Option 1: $3\sqrt{11}-7$

Option 2: $5\sqrt{13}-8$

Option 3: $5\sqrt{7}-11$

Option 4: $6\sqrt{11}-9$


Team Careers360 12th Jan, 2024
Answer (1)
Team Careers360 14th Jan, 2024

Correct Answer: $3\sqrt{11}-7$


Solution : Given: The length and breadth of a rectangle are 8 cm and 6 cm, respectively. The rectangle is cut on its four vertices such that the resulting figure is a regular octagon.

Let the sides of the octagon be $a$ cm.
From the figure, we get,
$a^2=\frac{(8–a)^2}{4}+\frac{(6–a)^2}{4}$
⇒ $a^2=16-4a+\frac{a^2}{4}+9-3a+\frac{a^2}{4}$
⇒ $a^2=\frac{a^2}{2}+25-7a$
⇒ $a^2+14a-50=0$
Solving this, we get,
$a=(3\sqrt{11}-7)$ cm
Hence, the correct answer is $3\sqrt{11}-7$.

SSC CGL Complete Guide

Candidates can download this ebook to know all about SSC CGL.

Download EBook

Know More About

Related Questions

TOEFL ® Registrations 2025
Apply
Accepted by 13,000 universities worldwide | Offered in 200+ countries | 40 million people have taken TOEFL Test
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