Question

$r$ and $r^{\prime}$ denote the angles inside an equilateral prism, as usual; in degrees.
Consider that during some time interval from $t=0$ to $t=t, r^{\prime}$ varies with time as $r^{\prime}=$ $10+t^2$. During this time $r$ will vary as (assume that $r$ and $r^{\prime}$ are in degree)

• A. $50-t^2$
• B. $50+t^2$
• C. $60-t^2$
• D. $60+t^2$

Answer 1

Answer: (A)

In a prism: $r+r^{\prime}=A \Rightarrow r=A-r^{\prime}$
$ \therefore r=60^{\circ}-\left(10+t^2\right)=50-t^2 $