Khyree cut a quadrilateral out of a piece of cardstock, but is not sure if the fi gure is a parallelogram or a rhombus. He measures the lengths of the opposite sides and determines them to be congruent. He measures the opposite angles of the quadrilateral and determines them also to be congruent. He measures one angle and is able to determine that the quadrilateral is a rhombus. What angle did he measure?

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?