The length of a building is 720 in. Use dimensional analysis to convert this quantity to yards.
1 answer:
Answer:
20 yards
Step-by-step explanation:
First, we have to know how to get from inches to yards. 12 inches = 1 foot, and 3 feet = 1 yard.
Next, we have
as a given. We want to multiply this by our conversions to get the end amount in yards.
We can first multiply our expression by 12 inches = 1 foot. To do this, we can set one number as the divisor and one as the dividend, e.g. 12 inches / 1 foot. However, to figure out which number should be the numerator/denominator, we first must examine our original expression. We want to multiply it by a value that cancels something out in conversion. To do this, we can have the same unit of something in the numerator in one and the denominator in the other in terms of what we're multiplying. Here, we can see that has inches on the top, so we want inches on the bottom in 12 inches = 1 foot. Therefore, we have
=
= 60 feet
=
We have feet as the numerator, so we want feet in the denominator in what we're multiplying this by. In 3 feet = 1 yard, we can multiply this to get
= 20 yards
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Answer:
The answer is hyperbola; (x')² - (y')² - 16 = 0 ⇒ answer (a)
Step-by-step explanation:
* At first lets talk about the general form of the conic equation
- Ax² + Bxy + Cy² + Dx + Ey + F = 0
∵ B² - 4AC < 0 , if a conic exists, it will be either a circle or an ellipse.
∵ B² - 4AC = 0 , if a conic exists, it will be a parabola.
∵ B² - 4AC > 0 , if a conic exists, it will be a hyperbola.
* Now we will study our equation:
xy = -8
∵ A = 0 , B = 1 , C = 0
∴ B² - 4 AC = (1)² - 4(0)(0) = 1 > 0
∴ B² - 4AC > 0
∴ The graph is hyperbola
* The equation xy = -8
∵ We have term xy that means we rotated the graph about
the origin by angle Ф
∵ Ф = π/4
∴ We rotated the x-axis and the y-axis by angle π/4
* That means the point (x' , y') it was point (x , y)
- Where x' = xcosФ - ysinФ and y' = xsinФ + ycosФ
∴ x' = xcos(π/4) - ysin(π/4) , y' = xsin(π/4) + ycos(π/4)
∴ x' = x/√2 - y/√2 = (x - y)/√2
∴ y' = x/√2 + y/√2 = (x + y)/√2
* Lets substitute x' and y' in the 1st answer
∵ (x')² - (y')² - 16 = 0
∴
(
* Lets open the bracket
∴
* Lets add the like terms
∴
* Simplify the fraction
∴ -2xy - 16 = 0
* Divide the equation by -2
∴ xy + 8 = 0
∴ xy = -8 ⇒ our equation
∴ Answer (a) is our answer
∴ The answer is hyperbola; (x')² - (y')² - 16 = 0
* Look at the graph:
- The black is the equation (x')² - (y')² - 16 = 0
- The purple is the equation xy = -8
- The red line is x'
- The blue line is y'
