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:
it is C
Step-by-step explanation:
32 and 34? does it specify whether they're consecutive odd or even numbers?
Answer:
The both on the right are the correct answers
Step-by-step explanation:
This is because rotational symmetry is defined as the property a shape has when it looks the same after some rotation by partial turns.
Answer:
Judy = $5/hr
Ben = $4/hr
Step-by-step explanation:
Judy's hours at work - x
Ben's hours at work - y
8x + 10y = 80
9x + 5y = 65
Given these two equations above, we get:
10y = 80 - 8x, which means y = 8 - 0.8x.
Substitute y in the second equation with 8 - 0.8x, so we have:
9x + 5 (8 - 0.8x) = 65
9x + 40 - 4x = 65
5x = 25
x = 5
Come back to the first equation, substitute x:
8*5 + 10y = 80
10y = 80 - 40
y = 4