Net present value of an energy-efficient motor. two 100-hp electric motors are being considered—call them "good" and "premium." the good motor draws 79 kw and costs $2400; the premium motor draws 77.5 kw and costs $2900. the motors run 1600 hours per year with electricity cost- ing $0.08/kwh. over a 20-year life, find the net present value of the cheaper alternative when a discount rate of 10% is assumed.

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.

answer the amount a seller is paid minus the cost of production;

false is correct i hope.

i might be