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:
As can be clearly seen from the attached diagram angles PBC and BAD are congruent by the Corresponding Angles Theorem AB acts as the transversal for the lines BC and AD which are parallel.
Also, it can be clearly seen that the angles ABC and BAT are congruent by the Alternate Interior Angles Theorem as AB acts as the transversal for the lines BC and TAD which are parallel.
Thus, the only option from the given list of options which matches the answer is Option A.
Thus, Option A is the correct option and thus the final answer.
Step-by-step explanation:
You find your slope with the equation
(y2-y1)/(x2-x1)
(-1-2)/ -4-1.5)
(-3)/(-5.5)
.54x is your slope
you then plug that into your equation.
y=mx+b
y=.54x+b
you substitute one of our coordinates.
(-4,-1)
-1=.54(-4)+b
-1=-3.45+b
+3.45
2.45=b
your equation is
y=.54x+2.45
standard form
y-.54x=2.45