The 3 methods of proving that triangle are congruent are:
SSS (side, side, side)
All sides of one triangle are congruent to a corresponding side in other triangle
ASA (angle, side, angle)
Two angles and included side of one triangle are congruent to angles and included side of other triangle
SAS (side, angle, side)
Two sides and included angle of one triangle are congruent to sides and included angle of other triangle
A rhomus is a quadrilateral whose four sides all have the same length.
Since RUMH is a rhombus, then RU = UM = MH = HR
Since RUBM is a rhombus, then RU = UB = BM = MR
Therefore when comparing corresponding sides of triangles RHM and UMB, we get
RH = UM
HM = MB
RM = UB
Triangles RHM and UMB are congruent by SSS
