what is the area of a circle if the radius is 5cm to three significant figures?

Question

0

1353

1

Guest Jun 24, 2014

+5478

+34

Best Answer

The formula for area of a circle is: ${\mathtt{A}} = {\mathtt{\pi}}{\mathtt{\,\times\,}}{{\mathtt{r}}}^{{\mathtt{2}}}$

Since the radius is 5, r² = 25 and:

${\mathtt{A}} = {\mathtt{\pi}}{\mathtt{\,\times\,}}{\mathtt{25}} \Rightarrow {\mathtt{A}} = {\mathtt{78.539\: \!816\: \!339\: \!744\: \!831}}$

Rounded to 3 significant figures: 78.5 cm²

kitty<3 Jun 24, 2014

kitty<3 · Answer 1 · 2014-06-24T10:08:30

The formula for area of a circle is: ${\mathtt{A}} = {\mathtt{\pi}}{\mathtt{\,\times\,}}{{\mathtt{r}}}^{{\mathtt{2}}}$

Since the radius is 5, r² = 25 and:

${\mathtt{A}} = {\mathtt{\pi}}{\mathtt{\,\times\,}}{\mathtt{25}} \Rightarrow {\mathtt{A}} = {\mathtt{78.539\: \!816\: \!339\: \!744\: \!831}}$

Rounded to 3 significant figures: 78.5 cm²