"you know that doubling the dimensions of a rectangular prism" explain

In the figure below, segment ac is congruent to segment ab: triangle abc with a segment joining vertex a to point d on side bc. side ab is congruent to side ac which statement is used to prove that angle abd is congruent to angle acd? segment ad bisects angle cab. triangle acd is similar to triangle abd. segment ad is congruent to segment ac. angle cab is congruent to angle cba.

Simplify the expression. -2/5(10+15m-20n)

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5