Can you give us what you measured ? (circles, lines, ...)
What
Dismas121 said should work, if you replace "ANGLE" by your angle dimension and "CIRCLE" by the right feature name.
You can do it by assignments without dimension :
ASSIGN/ANGLE=DEG2RAD(ANGLEBETWEEN(LIN1.IJK,LIN2.IJK))
ASSIGN/ARC_LEN=CIR1.R*ANGLE
