7. 3.14(12^2 - 10^2)=3.14(144-100) = 3.14(44)=138.16
8. A = piR^2 = 50.24. R^2 = 50.24/3.14 = 16. R = 4cm
9a) Perimeter of square is 4*18 = 72. Perimeter of circle is 2*pi*r. r=9in
perimeter of circle is then 2*3.14.9 = 56.52. Difference is 72-56.52 = 15.48
9b) Area of square is 18^2 = 324.
Area of circle is 3.14(9^2) = 254.34. Difference is the unshaded part
324-254.34 = 69.66in^2
15% off
15% off of 50
notice that 50 is 1/2 of hundred
15% of 100 is 15
therefor
15% of 50 is 15/2=7.5
that is discount
50-7.5=42.5
new price=$42.5
Do you have a picture of the graph? They formula put into y=mx+b is y=4/3+2
so the y intercept is 2 and the slope will be going upwards :)
