Answer:
Least interior angle = 36 degrees
Step-by-step explanation:
The ratio 4:5:6 means that the greatest exterior angle is 6/ (4+5+6) = 6/15 of the total value of the angles.
The sum of the exterior angles = 360 degrees so the greatest one is
= 360 * 6 / 15
= 360 * 2/5
= 144 degrees
This is adjacent to the smallest interior angle of the triangle so the answer is 180 - 144 = 36 degrees