To have a monopoly, barriers to entering the market must be so high that no other firms can enter. do network externalites create or remove barriers to entry? explain. network externalities a. removeremove barriers to entry because diseconomiesdiseconomies of scale are so large that one firm can supply the entire market at higherhigher average total cost than can two or more firms. b. remove barriers to entry because such externalities require multiple firms to provide the goods and services in the network. c. create barriers to entry because a firm efficiently offers products that satisfy consumer preferences. d. create barriers to entry because if a firm can attract enough customers initially, it can attract additional customers as its product's value increases by more people using it, which attracts even more customers. e. createcreate barriers to entry because consumption of a firm's product decreasesdecreases the value of goods and services produced by other firms.

steering wheels are always situated on the left side of the car.

always drive on the right side of the road.

white lines separate lanes of traffic traveling the same direction.

hashed or broken lines means you may change lanes when it is safe.

solid white lines mean stay in your lane.

yellow lines separate traffic moving in opposing directions.

hashed or broken yellow lines mean you can carefully pass, paying attention to oncoming traffic.

never cross a solid yellow line (or double yellow line).

when turning left at an intersection, pass in front of any cars that are turning left from the opposing direction (do not try to pass behind them).

use the left lane to pass other cars traveling your direction.

do not pass in the right lane unless absolutely necessary.

if you are driving in the far left hand lane and someone would like to pass you, move over to the right lane when it is safe to do so and allow them to pass.

you must always yield to pedestrians.

come to a complete stop whenever you see pedestrians trying to cross the street.

never pass a school bus if it has flashing red lights. wait until the lights have stopped.

be aware of bicyclists. often they share the road with cars and are supposed to also follow general traffic laws.

be particularly careful about driving in cities with bike lanes -- always check before turning that a bike is not coming.

it is mandatory to pull over or stop at an intersection to allow an emergency vehicle to pass you if you see one traveling with lights flashing and/or a siren running.

do not overuse your car horn. horns are used almost exclusively for emergency situations or for when you feel unsafe.

explanation:

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.