Which congruence postulate or theorem can be used to prove ΔADC ≅ ΔBCD if AD ≅ BC and AC ≅ BD?

Solve the system. -a+4b+2c=-8 3a+b-4c=9 b=-1 a.(0,11) ,-1,2) c.(1,1,-2) d.(2,-1,-1)

Which of the following statements is not true? a.parallel lines are lines in the same plane that never intersect. b.congruent figures have the same shape and same size angles and sides. c.similar figures must have the same shape and the same size. d.a rotation is when you turn a figure around a certain point.

What number line represents the solution set for the inequality -1/2 greater than or equal to 4