Final answer:
To find the measure of an arc or angle, one must understand the units of measurement. The optimum angle for maximum range is 45 degrees, whereas a 90 degrees or 0 degrees angle results in zero range.
Step-by-step explanation:
Finding the Measure of an Arc or Angle
When finding the measure of an arc or angle, it's essential to understand the unit of measurement. Angles can be measured in degrees, minutes, and seconds, with one degree containing 60 minutes of arc, and one minute containing 60 seconds of arc. However, the given options A. 59, B. 89, C. 80, D. 60 do not specify if they refer to degrees, minutes, or seconds, making it challenging to provide a precise answer without additional context. Typically, degrees are the standard unit for measuring angles.
Addressing the second part of the question, the optimum angle for the maximum range of a projectile on level ground is commonly known to be 45 degrees, due to the optimal balance between vertical and horizontal components of the projectile's velocity.
For the range to be zero, the projectile needs to be either launched straight up or not launched at all, thus at a 90 degrees or 0 degrees angle. Therefore, from the given options, the answer would be 90° or 0°.