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What is the diameter of a circle whose circumference is 5?

Mar 23, 2018

$\text{diameter "=5/pi~~1.59" to 2 dec. places}$

Explanation:

$\text{the circumference (C) of a circle is}$

•color(white)(x)C=pidlarrcolor(blue)"d is the diameter"

$\text{here } C = 5$

$\Rightarrow \pi d = 5$

$\text{divide both sides by } \pi$

$\frac{\cancel{\pi} d}{\cancel{\pi}} = \frac{5}{\pi}$

$\Rightarrow d = \frac{5}{\pi} \approx 1.59 \text{ to 2 dec. places}$

Mar 23, 2018

The diameter is $\frac{35}{22}$.

Explanation:

The diameter of a circle is twice its radius.

We can find the radius of the circle by the equation

$\text{circumference} = 2 \pi r$

Now, just plug it in as $5 = 2 \pi r$

$5 = 2 \cdot \left(\frac{22}{7}\right) r$

$r = 5 \cdot \left(\frac{1}{2}\right) \cdot \left(\frac{7}{22}\right)$

$r = \frac{35}{44}$

Since the diameter is twice the radius, $d = \frac{35}{44} \cdot 2$

$d = \frac{35}{22}$