Question
Two cones with same base radius $8\ cm$ and height $15\ cm$ are joined together along their bases. Find the surface area of the shape formed.
✓
Answer
If two cones with same base and height are joined together along their bases, then the shape so formed is look like as figure shown.
Given that, radius of cone, $r = 8\ cm$ and height o cone, $h = 15\ cm$
So, surface area of the shape so formed
= curved area of first cone $\times$ Curved surface area of secound cone
= $2$ surface area of cone
$=2\times\pi\text{rl}=2\times\pi\times\text{r}\times\sqrt{\text{r}^2+\text{h}^2}$
$=2\times\frac{22}{7}\times8\times\sqrt{(8)^2+(15)^2}$
$=\frac{2\times22\times8\times\sqrt{64+225}}{7}$
$=\frac{44\times8\times\sqrt{289}}{7}=\frac{44\times8\times17}{7}$
$=\frac{5984}{7}=854.85\text{cm}^2$
$=855\text{cm}^2$
Hence, the surface areaq of the shape so formed is $855cm^2$.
Given that, radius of cone, $r = 8\ cm$ and height o cone, $h = 15\ cm$
So, surface area of the shape so formed
= curved area of first cone $\times$ Curved surface area of secound cone
= $2$ surface area of cone
$=2\times\pi\text{rl}=2\times\pi\times\text{r}\times\sqrt{\text{r}^2+\text{h}^2}$
$=2\times\frac{22}{7}\times8\times\sqrt{(8)^2+(15)^2}$
$=\frac{2\times22\times8\times\sqrt{64+225}}{7}$
$=\frac{44\times8\times\sqrt{289}}{7}=\frac{44\times8\times17}{7}$
$=\frac{5984}{7}=854.85\text{cm}^2$
$=855\text{cm}^2$
Hence, the surface areaq of the shape so formed is $855cm^2$.
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