If there are 360 g of radioactive material with a half life (decreased by half or 50% )of 1 hour, how much of the radioactive material will be left after 4 hours ?

After 1 hour, 360 g decays to 180 g.

After another hour (total 2 hours), 180 g decays to 90 g.

After another hour (total 3), 90 g decays to 45 g.

After one more (total 4), 45 g decays to 22.5 g.

More quickly, with a half-life of 1 hour, the 360 g of starting material decays to

(360 g) / 2⁴ = 22.5 g

In general, if the half-life is 1 hour, then after n hours, an initial amount A of this substance decays according to

A / 2ⁿ

2. angles qrt and qst both measures 156 degrees.

step-by-step explanation:  

we have been given a diagram of a circle and we are told that measure of arc qvt is 156 degrees.  

we can see from our given diagram that angle qrt and angle qst subtends to arc qvt.

since we know that angles subtended by the same arc at the circumference are always equal.

by angle subtended by same arc theorem, measure of angle qrt and angle qst will be equal to the measure of arc qvt.

therefore, angles qrt and qst both measures 156 degrees and 2nd statement is the correct choice.

answer: the resulting cross section is a rectangle. solution: a plane parallel to the base of a triangular prism will intersect a cross section that is the same shape as its bases. so the cross section is a triangle.

step-by-step explanation: