A 4ft pole casts a shadow 6ft long. At the same time a wall casts a shadow 18ft. long. How tall is the wall?

12 ft

Step-by-step explanation:

Write and solve an equation of ratios:

 6 ft        4 ft

=

 18 ft        w

Cross multiplying, we get:  6w = 72 ft^2, so w = 12 ft

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.