Answer:
The answer is C.
Step-by-step explanation:
Hope this helps
The value of x is 11
Because both the angles should be equal
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:
7.7
Step-by-step explanation:
The area of the wall is 4 * 2 = 8.
The radius of each clock is 0.3 / 2 = 0.15.
The area of all 4 circles is 4 * (πr²) = 4 * 3.14 * 0.15² = 0.3.
8 - 0.3 = 7.7