Answer: The lamppost is 7 feet 2 inches
Step-by-step explanation: If Ann measured her own height and her shadow, then what she used is a ratio between both measurements. If she can measure the shadow of the lamppost, then she can use the same ratio of her height and it’s shadow to derive the correct measurement of the lamppost.
If Ann’s height was measured as 5 feet 3 inches, and her shadow was 8 feet 9 inches, the ratio between them can be expressed as 3:5.
Reduce both dimensions to the same unit, that is, inches. (Remember 12 inches = 1 foot)
Ratio = 63/105
Reduce to the least fraction
Ratio = 3/5
If the height of the lamppost is H, then
H/144 = 3/5
H = (144 x3)/5
H = 86.4
Therefore the lamppost is approximately 86 inches, that is 7 feet and 2 inches tall.
Answer:
90 degree rotation in the clockwise direction.
Step-by-step explanation:
Point A transforms to A'
- that is x coordinate: 2 ---> 3
and y coordinate 3 ---> -2
So the rotation is clockwise from Quadrant1 to Quadrant 4.
The slope of OA = 3/2 and the slope of OA' = -2/3.
The product of these slopes = 3/2 * -2/3 = -1 so the lines are perpendicular - that is the line has passed through an angle of 90 degrees.
A similar result occurs if we consider points B, C and D.
Answer:
Obtuse Angle.
-16.66666667
Step-by-step explanation:
Answer:
2.29 ft of side length and 1.14 height
Step-by-step explanation:
a) Volume V = x2h, where x is side of square base and h is hite.
Then surface area S = x2 + 4xh because box is open.
b) From V = x2h = 6 we have h = 6/x2.
Substitude in formula for surface area: S = x2 + 4x·6/x2, S = x2 + 24/x.
We get S as function of one variable x. To get minimum we have to find derivative S' = 2x - 24/x2 = 0, from here 2x3 - 24 = 0, x3 = 12, x = (12)1/3 ≅ 2.29 ft.
Then h = 6/(12)2/3 = (12)1/3/2 ≅ 1.14 ft.
To prove that we have minimum let get second derivative: S'' = 2 + 48/x3, S''(121/3) = 2 + 48/12 = 6 > 0.
And because by second derivative test we have minimum: Smin = (12)2/3 + 4(12)1/3(12)1/3/2 = 3(12)2/3 ≅ 15.72 ft2
