Mensuration – II (Area of Circle) — MATHS STD 7 — Question
Gujarat BoardEnglish MediumSTD 7MATHSMensuration – II (Area of Circle)3 Marks
Question
A road which is $7m$ wide surrounds a circular park whose circumference is $352m$. Find the area of of road.
✓
Answer
Circumference of the circular park $=2\pi\text{r}=352\text{m}$
$=2\pi\text{r}=352$
$=2\times\frac{22}{7}\times\text{r}=352$
$=\text{r}=56\text{m}$
Radius of the path including the $7m$ wide road $=(\text{r}+7)$
$=56+7=63\text{m}$
$\therefore$ Area of the road: $=\pi\times(63)^2-\pi\times(56)^2$
$=\frac{22}{7}\times63\times63-\frac{22}{7}\times56\times56$
$=22[9\times63-8\times56]$
$=22[567-448]$
$=2618\text{m}^2$
$\therefore$ Area of the road $=2618\text{m}^2$
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