more integrating (1 Viewer)

[otakuworld]

I attempted the first question and got like halfway but I don't know how to do find volumes of semicircles in integration.
There are 2 questions I'm stuck on for the first image its on the right question b) and 16. Sorry for the bad quality

 

[jazz519]

What was the answer to them (just so we don't have a repeat of my silly mistakes like yesterday)

https://drive.google.com/open?id=1r-aLboDIUx7t348sD0eGUgGv_3WAapOF
https://drive.google.com/file/d/1c89Lq6ZYl02mjjLZctK4alFyMUtcY2i2/view?usp=sharing
https://drive.google.com/open?id=1J7-RplcEyk5q1UKSdQQnewP1MMPxHZq_
https://drive.google.com/open?id=1cP-4ktPSCfOe8LhresWiy-VXWE57az-2

 

[ichila101]

https://drive.google.com/open?id=12H3D5IiDjcj9iB1OVNjLOWVuC_KzGzyJ

https://drive.google.com/open?id=1nVC_PWCpxxN3Q3v2DZN4uogw5_pN8jUQ

Edit: Shoot they're both upside down and the first mightttt be wrong sorry about that

Edit2: Yeah I made a mistake in my first one Jazz got it

 

[otakuworld]

huh, this was actually how I did it at first but I thought it was wrong. Thanks again I remember you from yesterday! ヾ(☆▽☆)
The answers correct

 

[otakuworld]

I can easily flip the image, thank you!