Answer
Refer to the figure
Work Step by Step
$\dfrac{21 \pi}{4} = 2 \pi + 2 \pi + \dfrac{5 \pi}{4}$
To draw an angle of $\dfrac{21 \pi}{4}$ in standard position, make two full revolutions in the anti-clockwise direction followed by a $\dfrac{5\pi}{4}$ rotation in the same direction.
A rotation of $\dfrac{5 \pi}{4} $ is $\dfrac{5}{8}$ of a revolution.
The initial side is represented by the red line.
The terminal side of the angle in its standard position is represented by the blue line.
