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.
I think multiplication but I’m not sure sorry
Answer:
The answer is 2240m².
Step-by-step explanation:
Given that the formula of area of trapezium is A = 1/2×(a+b)×h where a and b represents the length and h is height :






Answer:
5
Step-by-step explanation:
speed=d÷t.
s=1/4=1/20
cross multiply your equation