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:
B. 1:2800
Step-by-step explanation:
448 / .16 = 2800
1:2800
Feel free to let me know if you need more help! :)
Answer: 6.4
Step-by-step explanation: If rounding to one decimal place, your answer would be 6.4.
49.6 divided by 7.8 = 6.35897435...
Now, we see that after the 3 (The first decimal place) there is a five. Because we are rounding to the first decimal place the second decimal place will tell us to round up or down. In this case because it's a five, we would round up.
Answer:
My brother took this test and said it was 35. Im not sure but try it
Step-by-step explanation: