Question

if m∠nsm = 100°, then what is m∠msp?

Explanation:

Step1: Identify angle - relationship

Assume $\angle NSM$ and $\angle MSP$ are supplementary angles (since no other information is given and they seem to form a linear - pair). Supplementary angles add up to $180^{\circ}$.
Let $m\angle NSM = 100^{\circ}$ and $m\angle MSP=x$. Then $m\angle NSM + m\angle MSP=180^{\circ}$.

Step2: Solve for $m\angle MSP$

We have the equation $100^{\circ}+x = 180^{\circ}$.
Subtract $100^{\circ}$ from both sides: $x=180^{\circ}- 100^{\circ}$.
$x = 80^{\circ}$

Answer:

$80^{\circ}$