Please help with #9 and #10

0 and 7 For questions 8, 9, 10: Note that r2 + 12 = 12 is the equation of a circle of radius 1. Solving for y we have y = v1 - a2, when y is positive. 8. Compute the length of the curve y = v1 - 12 between a = 0 and r = 1 (part of a circle.) 9. Compute the surface of revolution of y = \\1 - r2 around the r-axis between a = () and x = 1 (part of a sphere.) 10. Compute the volume of the region obtain by revolution of y = v1 - r2 around the I-axis between x = 0 and z = 1 (part of a ball.)