Perform the calculation.
-$90 ^ { \circ } - 19 ^ { \circ } 39 ^ { \prime }$
A) $70 ^ { \circ } 39 ^ { \prime }$
B) $70 ^ { \circ } 21 ^ { \prime }$
C) $71 ^ { \circ } 39 ^ { \prime }$
D) $71 ^ { \circ } 21 ^ { \prime }$

Question

Quizplus · Accepted Answer

To subtract angles, you subtract the minutes from minutes and degrees from degrees. If the minutes in the subtrahend are larger than in the minuend, you need to borrow 1 degree (which is equal to 60 minutes) from the degrees. Here, $90^\circ - 19^\circ = 71^\circ$ and $60' - 39' = 21'$, so after borrowing, the answer is $70^\circ 21'$.

Perform the Calculation 90∘−19∘39′90 ^ { \circ } - 19 ^ { \circ } 39 ^ { \prime }90∘−19∘39′

Perform the Calculation $90 ^ { \circ } - 19 ^ { \circ } 39 ^ { \prime }$