$3293.5$ \displaystyle {{\text{m}}^{2}}$$

**Explanation**:

Length of rectangular field = $L=70Âm$

Breadth of rectangular field = $B=52Âm$

So, Area of the field = $LÃ—B=70Ã—52=3640$

Area of the field is $3640$ \displaystyle {{\text{m}}^{2}}$$

And,

Area it can graze = Area of quadrant of radius $21Âm= $ \displaystyle \dfrac{1}{4}$â€‹Ã— $ \displaystyle \dfrac{22}{7}$â€‹Ã—21Ã—21=346.5$ \displaystyle {{\text{m}}^{2}}$$

Area it can graze = Area of quadrant of radius $21Âm= $ \displaystyle \dfrac{1}{4}$â€‹Ã— $ \displaystyle \dfrac{22}{7}$â€‹Ã—21Ã—21=346.5$ \displaystyle {{\text{m}}^{2}}$$

Area not available for grazing = (Area of the field) – (Area of quadrant of radius $21Âm)$

$=3640âˆ’346.5=3293.5$ \displaystyle {{\text{m}}^{2}}$$

Thus, $3293.5$ \displaystyle {{\text{m}}^{2}}$$Â area is left ungrazed.