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.
There are 4 quarts in 1 gallon, so a rate of 120 gallons per minute converts to 4 x 120 = 480 quarts per minute. To find the per hour rate, we simply multiply our per minute rate by 60, obtaining 480 x 60 = 28800 quarts per hour.
Answer:
second x -1,-3,-5 y 1 3 5 for proportional relation
To answer this question you have to create a system of equations. The first equation will be that Devi's money (x) equals her brother's money (y), or x = y. The next equation would be that (3/5)x + (7/10)y = 78. You than can substitute x in for y because x = y. The equation would know be (3/5)x + (7/10)x = 78. You then combine the like terms to create an equation of (13/10)x = 78. Then, multiply both sides by 10 / 13 in order to isolate x. This will create the equation x = 60. This means that Devi and her brother each had 60 dollars. You then find out how much they spent and add it together. You can do so with the equation (2/5)x + (3/10)y = z, with z being total money spent. You substitute 60 in for x and for y then solve. When you solve you see that 24 + 18 = z, or that z equals 42. In other words, they spent 42 dollars altogether.
P = 2(L + W)
P = 128
L = 2W + 4
128 = 2(2W + 4 + W)
128 = 2(3W + 4)
128 = 6W + 8
128 - 8 = 6W
120 = 6W
120/6 = W
20 = W <=== width is 20 ft
L = 2W + 4
L = 2(20) + 4
L = 40 + 4
L = 44 <=== length is 44 ft
