Convert $-210^{\circ}$ to radian measure in terms of $\pi$. radians

Step 1 ：Given the angle in degrees is -210.

Step 2 ：We use the formula to convert degrees to radians: radians = degrees * (π / 180).

Step 3 ：Substitute -210 into the formula: radians = -210 * (π / 180).

Step 4 ：Simplify the expression to get the radian measure: radians = -3.6651914291880923.

Step 5 ：\(\boxed{-3.6651914291880923}\) or approximately \(\boxed{-\frac{7\pi}{6}}\) is the radian measure of -210 degrees.