Answer:
Obtuse
Explanation:
4pi/5 = 144°
You could estimate 4pi/5 or do a conversion calculation.
To estimate, see unit circle attached. 4/5 is somewhere near 3/4 and 5/6 (3/4 is .75, 4/5 is .8, and 5/6 is .8333) also see on the unit circle that pi = 180° you can estimate that 4/5 of pi is going to be bigger than half of pi. 90° (half of pi) is where you go from acute to obtuse.
You can just convert radians (4pi/5 is angle measure in radians)to degrees.
Use pi = 180°
4pi/5 × 180/pi
cancel pi
= 4/5 × 180°
= 4×180 / 5
= 720/5
= 144°
A 144° angle is obtuse.