Given that AD is the perpendicular bisector of BC, AB=21.3, AC=21.3, and DC=9.1, identify BC. a) BC = 42.6
b) BC = 18.2
c) BC = 9.1
d) BC = 4.55

sorry i can't upload a picture of the triangle but this is from an luoa assignment. i know it's not C

The surface area (sa) of a cube with a as the length of each of its sides is given by the formula . if the surface area is known, how can you rewrite the formula to find its side?

1- is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis. 2- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis. 3- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in part b?

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?