Dear friends, Please read our latest blog post for an important announcement about the website. ❤, The Socratic Team

# What is the circumference of a circle with an area of 49 pi inches^2?

Then teach the underlying concepts
Don't copy without citing sources
preview
?

#### Explanation

Explain in detail...

#### Explanation:

I want someone to double check my answer

8
Jan 26, 2016

$44$ $i$$n c h e s$

#### Explanation:

$L e t$ $r a \mathrm{di} u s$ $o$$f$ $c i$$r c l$$e$$=$$r$
$A r e a$ $o$$f$ $c i r$$c$$l$$e$$=$ $\pi {r}^{2} = 49 \pi$ $i$$n c h e {s}^{2}$

$N o t e$ $t h$$a t$ $\pi = \frac{22}{7}$

$\rightarrow \pi {r}^{2} = 49 \pi$

$\rightarrow {r}^{2} = \frac{49 \pi}{\pi}$

$\rightarrow {r}^{2} = 49$

$\rightarrow r = \sqrt{49} = 7$

$S o , w e$ $n$$e e d$ $t$$o$ $f i$$n d$ $c i$$r c u$$m f$$e r e n c e$ $o$$f$ $c i$$r c l$$e$

$C i$$r c u m f e r e n c e$ $o$$f$ $c i$$r c l$$e$ $= 2 \pi r$

$\rightarrow 2 \pi r = 2 \pi \left(7\right) = 14 \pi$

$\rightarrow = 14 \cdot \frac{22}{7} = 2 \cdot 22 = 44$ $i$$n c h e s$

Then teach the underlying concepts
Don't copy without citing sources
preview
?

#### Explanation

Explain in detail...

#### Explanation:

I want someone to double check my answer

1
May 2, 2018

$C = 14 \pi = 43.982 \approx 44$ inches

#### Explanation:

To find the circumference, you need the radius.

You can find the length of the radius from the area.
(Divide by $\pi$ and then find the square root)

$\pi {r}^{2} = A \text{ } \rightarrow r = \sqrt{\frac{A}{\pi}}$

The radius is $r = \sqrt{\frac{49 \cancel{\pi}}{\cancel{\pi}}}$

$r = \sqrt{49} = 7$ inches

$C = 2 \pi r$

$C = 2 \pi \left(7\right)$

$C = 14 \pi$

You can give the answer in this form using $\pi$ because that is how the area was given,

Or if you calculate it:

Using $\pi \approx \frac{22}{7}$

$14 \times \frac{22}{7}$

$= 44$ inches

Using the calculator value of $\pi$ which is more accurate gives:

$14 \pi = 43.982$ inches

• 51 minutes ago
• An hour ago
• An hour ago
• An hour ago
• 4 minutes ago
• 8 minutes ago
• 12 minutes ago
• 20 minutes ago
• 27 minutes ago
• 37 minutes ago
• 51 minutes ago
• An hour ago
• An hour ago
• An hour ago
• Tri
• Pre
• Phy
• Org
• Ana
• Geo
• Env
• Bio
• Cal
• Ast
• Psy
• Alg
• Ast
• Eng
• U.S
• Soc
• Ear
• Che
• Wor
• Sta
• Pre