Answer
(a) $\sin{1} \approx 0.85$
(b) $\sin{1} \approx 0.84$
The two values are quite close, with a minimal difference of $0.01$.
Work Step by Step
RECALL:
$\sin{t} = y
\\\cos{t} =x$
(a)
The value of $\color{red}\sin{\color{red}1}$ is equal to the y-coordinate of the red point shown in the attached image below.
Thus, using the given figure, $\color{red}\sin{\color{red}1} \color{red}\approx \color{red}0\color{red}.\color{red}8\color{red}5$.
(b)
Using a calculator in RAD mode gives:
$\sin{1} \approx 0.84$
The two values are quite close, with a minimal difference of $0.01$.
