MCQ
The total surface area of a cone whose radius is $\frac{\text{r}}{2}$ and slant height $2l$ is:
- A$\pi\text{r}(1+\text{r})$
- B$2\pi\text{r}(1+\text{r})$
- ✓$\pi\text{r}(1+\frac{\text{r}}{4})$
- D$2\pi\text{r}1$
✓
Answer
Correct option: C.
$\pi\text{r}(1+\frac{\text{r}}{4})$
$TSA$ of Cone $=\pi\text{r}\text{l}+\pi\text{r}^2$
$=\pi\text{r}(1+\pi)$
$=\pi\frac{\text{r}}{2}(2l+\frac{\text{r}}{2})$
$=\pi\text{r}(1+\frac{\text{r}}{4})$
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