From the setup of the problem, the "length of the top of the bookcase, measured along the attic ceiling" will be the hypotenuse of a right triangle, the length "AB". We have both the angle between AB and AC and the length of AC (3.24 meters), so we can use trigonometric identities.
The cosine of the 40 degree angle between AB and AC is equivalent to the length of AC divided by the length of AB. Equivalently, we have:

where "h", the hypotenuse, is the length we want. Rearranging the formula to solve for h we have that

which is 4.2295... meters. Converting to centimeters (multiplying by 100) we have that h = 422.95... centimeters, or if we round the value, h = 423 centimeters.
Answer:
Step-by-step explanation:
They are also similar.
Both have 4 right angles. Both have 2 sets of parallel lines. Both have 4 equal sides.
But I think you are supposed to answer if figure 1 is similar to figure 2 and figure two is similar to figure 3 then by the transitive property, figure 1 is similar to figure 3.
12 would be the only zero if you meant to write the equation as y=(x-12)(3-10)