Question : In $\Delta \mathrm{ABC}$, a line parallel to side $\mathrm{BC}$ cuts the sides $\mathrm{AB}$ and $\mathrm{AC}$ at points $\mathrm{D}$ and $\mathrm{E}$ respectively and also point $\mathrm{D}$ divides $\mathrm{AB}$ in the ratio of $\mathrm{1 : 4}$. If the area of $\Delta \mathrm{ABC}$ is $200\;\mathrm{cm^2}$, then what is the area (in $\mathrm{cm^2}$) of quadrilateral $\mathrm{DECB}$?

Option 1: 192

Option 2: 50

Option 3: 120

Option 4: 96


Team Careers360 10th Jan, 2024
Answer (1)
Team Careers360 12th Jan, 2024

Correct Answer: 192


Solution :
Given: $\mathrm{AD:DB=1:4}$ and the area of $\Delta \mathrm{ABC}$ is $200\;\mathrm{cm^2}$.
In $\Delta \mathrm{ABC}$,
$\mathrm{DE}\parallel\mathrm{BC}$
So, $\Delta \mathrm{ADE}\sim\Delta \mathrm{ABC}$,
The ratio of the areas of two similar triangles is equal to the square of the ratio of their corresponding sides.
⇒ $\frac{\text{Area of $\Delta \mathrm{ADE}$}}{{\text{Area of $\Delta \mathrm{ABC}$}}}=(\frac{\mathrm{AD}}{\mathrm{AB}})^2$
⇒ $\frac{\text{Area of $\Delta \mathrm{ADE}$}}{{200}}=(\frac{\mathrm{1}}{\mathrm{5}})^2$
⇒ $\frac{\text{Area of $\Delta \mathrm{ADE}$}}{{200}}=(\frac{\mathrm{1}}{\mathrm{25}})$
⇒ $\text{Area of $\Delta \mathrm{ADE}$}=8\;\mathrm{cm^2}$
The area of quadrilateral $\mathrm{DECB}=\text{Area of $\Delta \mathrm{ABC}$}-\text{Area of $\Delta \mathrm{ADE}$}$
$=200\;\mathrm{cm^2}-8\;\mathrm{cm^2}=192\;\mathrm{cm^2}$
Hence, the correct answer is $192$.

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
GRE ® Registrations 2024
Apply
Apply for GRE® Test now & save 10% with ApplyShop Gift Card | World's most used Admission Test for Graduate & Professional Schools
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