Angles subtended by opposite arcs
When a quadrilateral is inscribed on a circle, the angles that are opposite each other are related.
Measure ∠D and ∠F. What do they add up to? Move the points around and try again.
Nets of Solids
Circle Theorems, Angles in a semi circle
SeeSaw - multiplying signed numbers
Yoshimoto cube and flexahedron basic elements
testfileWed Aug 08 20:27:20 CEST 20180.6069080760601498
9.1.3 Pre #1103407 option C
9.1.3 Pre #1103407 correct A
coplanar and point and lines