would we still have 90 degrees angle at B? Prob27Chap1

Hi

Please have a look on the attachment and kindly help me with the query there. Thanks a lot.

Regards
PG

PG,

Q: OAP etc. MUST be right triangles because their angles are defined by the length of the sides of the triangles.

The ultimate rise of r is into the z-axis. There would still be a 90° relationship, but the projection on the y-axis would be zero, so no triangle would be formed.

Ratch