Find the gcf of each pair of numbers.

10 and 45 21 and 40 60 and 72 28 and 32 30 and 45 25 and 90 28 and 70 45 and 81 55 and 77

How many $20 bills do you need to have to make $280

In the polynomial below, what number should replace the question mark to produce a difference of squares? x2 + ? x - 36

Si la base de un triángulo isósceles mide 70 m y el ángulo opuesto a ésta mide 58°; entonces ¿cuánto mide la altura de dicho triángulo? a) 21.87 m. b) 40.01 m. c) 43.74 m. d) 63.14 m.