Final answer:
To find the value of m₂₁, divide 220 by 60 and multiply the result by 21.
Step-by-step explanation:
To determine the value of m₂₁ in the given expression, we need to follow the order of operations.
First, we divide 220 by 60 to get 3.66667. Next, we multiply 3.66667 by 21 to get the value of m₂₁.
m₂₁ = 3.66667 x 21 = 76.66667
Therefore, the closest option to the calculated value of m₂₁ is 80º. So, the correct answer is c. 80.