Suppose a tax equal to the value of the marginal external cost at the optimal output is imposed on a pollution generating good. All of the following will result from the tax except
A) an increase in demand for the good.
B) an increase in the equilibrium market price.
C) a decrease in the equilibrium quantity produced and consumed
D) a decrease in market supply of the good.

C) a decrease in the equilibrium quantity produced and consumed

Explanation:

Marginal external cost is the change in the cost to parties other than the producer or buyer of a good or service due to the production of an extra unit of the good or service.

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.