Convert the angles to degrees. Remember there are 2pi radians in a circle, and a circle has 360 degrees, so conversion factor is 180degrees/pi. Then you can easily approximate the reference angle. Remember you make the reference angle from the positive x-axis and the reference angle will be the angle between the terminal side and the nearest x-axis (either positive side or negative side of the x-axis).
1)

2)
Answer:
-1/2 > x > -3
Step-by-step explanation:
i)
-2x+3>4
-2x> 1
x < -1/2
ii)
-2x+3<9
-2x<6
x > -3
= -1/2 > x > -3
Trevor’s estimate is UNDERestimate because 8*6 is 48 and 8.33*6.2 = 51.646
6x-4-x^2
6(3)-4-x^2
18-4-x^2
14-x^2
Hope it helps
2 1/4=2.25
2.25*5.75-2.25*3.25=2.25(5.75-2.25)=2.25*3.50=7.875 ≈ 7.88