David wants to buy a pizza and go to the movies. however, he only has enough money to do one or the other. in order to decide what to spend his limited money on, what must david do?

D. Engage in a rational decision making process

Explanation:

David is facing an issue all people face at some point. Money is a scarce resource and decisions must be made with how to use that money. IN this situation, David would make the best decision by choosing to engage in a rational decision making process. This means he would weigh out the marginal costs and marginal benefits of using his money in each way.

bd = 9 cm

step-by-step explanation:

in a 30°-60°-90° triangle, the ratio of side lengths is 1 : √3 : 2. that is, the longest side (hypotenuse) is twice the length of the shortest side.

all of the triangles in your geometry are 30°-60°-90° triangles. ac is the hypotenuse of δacd, and the short side of δabc.

the short side ad of δacd will be half the length of ac, so 3 cm. the hypotenuse ab of δabc will be twice the length of ac, so 12 cm. segment bd is the difference of the lengths ab and ad, so is

bd = ab -ad

bd = 12 cm - 3 cm = 9 cm

comment on side length ratios

you can figure the ratios of side lengths in a 30°-60°-90° triangle by considering the trig ratios of the angles. or you can figure the length of the altitude of an equilateral triangle of side length 2 using the pythagorean theorem.