Which relation is a function? a) {(2,1),(3,1),(4,1),(5,1)]
b) {(1,2),(1,3),(1,4),(1,5)}
c) {(2,3),(3,2),(4,2),(2,4)}
d) {(1,6),(2,8),(3,9),(3,12)}

In the following diagram it is given that dec,ab || dc, ad || eb, and ad is congruent to bc. a)why isn't abc a parallelogram even though it has a pair of parallel sides and a pair of congruent sides b)explain why be must be congruent to bc. further explain what type of triangle this makes triangle abc and what it tells you about angle 1 and angle 2c) finally why must angle 3 be congruent to angle 1? further, explain why we know that angle 3 is congruent to angle 2