Strontium 90 is a radioactive material that decays according to the function
A(t)=A0e−0.0244t, where A0 is the initial amount present and A is the amount present at time t (in years). Assume that a scientist has a sample of 400 grams of strontium 90.

a) what is the decay rate of strontium 90?
b) how much strontium 90 is left after 40 years
c) when will only 300 grams of strontium 90 be left?
d) what is the half life of strontium 90?

Circle d circumscribes abc and abe. which statements about the triangles are true? statement i: the perpendicular bisectors of abc intersect at the same point as those of abe. statement ii: the distance from c to d is the same as the distance from d to e. statement iii: bisects cde. statement iv: the angle bisectors of abc intersect at the same point as those of abe. a. i only b. i and ii c. ii and iv d. i and iii e. iii and iv