A figure cannot be determined as congruent from three angles alone. In order for two shapes to be congruent, all corresponding parts must be congruent. This means all the sides and angles of the two shapes must be the same in order for the two shapes to be congruent. If we know all the angles are the same, the sides could still be different lengths, so this does not prove congruency.
There is one very important exception to the rule that multiplying or dividing an inequality is the same as multiplying or dividing an equation. Whenever you multiply or divide an inequality by a negative number, you must flip the inequality sign.
