(0.4)² = (0.4).(0.4) = 0.16
His error is, instead of raising (0.4) to exponent 2, he multiplied (0.4) by 2 , obviously which is wrong
Assuming that is a complementary angle meaning that the angle will add up to 90' your answer should be:
78 <-----
Answer : 2.5
Solution:
To find the halfway number it means that you need to find the middle most value using the formula
Mid value = (X + Y) / 2
So in this case it would be,
Mid value = (-15 + 20 ) / 2
Mid Value = ( 5 ) / 2
Mid Value = 2.5 answer
Hope this helps in understanding the question! :)
Note : do not forget the negative sign as it will change the answer and may cost you marks!