vector, vertex, vertical
right.
x axsis
the words geometry comes from the greek word geometria.
volume, vertical angles
Presumably at the birth of the Universe.
Geometry
eicosohedron
right.
Tangent.
Whole Number
Since this sentence is lacking a predicate, it is virtually impossible to answer. "Geometry words that start with r" is a legitimate noun phrase, but is so incomplete that it cannot be answered.
diameter, diallation
I know one is X-Axis
x axsis
Words that start with the letter V are, valley, violin, violet and violence. Virus, viola, vengeance and vast all start with V.
Wedge and Whole number :)
voltage