Question : The radius of a right circular cone is 3 cm and its height is 4 cm. The total surface area of a cone is:
Option 1: 48.4 cm2
Option 2: 64.4 cm2
Option 3: 96.4 cm2
Option 4: 75.4 cm2
Correct Answer: 75.4 cm 2
Solution : The total surface area of a right circular cone of radius $r$ and slant height $l$ is $\pi r (r + l)$. Given: $r = 3 \, \text{cm}$ and $h = 4 \, \text{cm}$. $⇒l = \sqrt{r^2 + h^2}$ $⇒l = \sqrt{3^2 + 4^2} = 5 \, \text{cm}$ The total surface area of a right circular cone $= \pi r (r + l)$ where \(r\) is the radius of the base of the cone and \(l\) is the slant height of the cone. The total surface area of a right circular cone $= \frac{22}{7}\times 3 \, \text{cm} \times (3 \, \text{cm} + 5 \, \text{cm}) $ The total surface area of a right circular cone $= 75.4 \, \text{cm}^2$ Hence, the correct answer is 75.4 cm 2 .
Result | Eligibility | Application | Selection Process | Cutoff | Admit Card | Preparation Tips
Question : The total surface area of a right circular cylinder is 1848 cm2. The ratio of its total surface area to the curved surface area is 3 : 1. The volume of the cylinder is: (Take $\pi=\frac{22}{7}$)
Question : The perimeter of the base of a right circular cone is 132 cm. If the height of the cone is 72 cm, then What is the total surface area (in cm2) of the cone?
Question : What is the total surface area of a solid right circular cylinder of radius 7 cm and height 8 cm?$(\pi=\frac{22}{7})$
Question : What is the difference between the total surface area and the curved surface area of a cone whose radius is 35 cm? (Take $\pi=\frac{22}{7}$)
Question : The area of the base of a cone is 616 cm2. If its slant height is 20 cm, then what is the total surface area of the cone? [Use $\pi$ = $\frac{22}{7}$]
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile