30. Crafts. A circular coffee table has a diameter of 5 ft. What will it cost to have the top refinished if the company charges $3 per square foot for the refinishing? = $3.00 x 5 ft =
38. Construction. An A-frame cabin has a triangular front with a base of 30 ft and a height of 20 ft. If the front is to be glass that costs $3 per square foot, what will the glass cost? = 30 ft x 20 ft = 50 ft
44. The distance from Philadelphia to Sea Isle City is 100 mi. A car was driven this distance using tires with a radius of 14 in. How many revolutions of each tire occurred on the trip? 100 mi x 14 in =
2006-11-30 03:52:21 · 6 answers · asked by single2mingle22000 2 in Science & Mathematics ➔ Mathematics
#30 is 58.88. Area = pie*(diameter/2) squared
#38 is 900. Area of triangle = .5 base*height
#44 is 73,950
Circumference = Pi X Diameter
So 3.14 X 2.33 ft. (14 in tireX 2 to convert to diameter)/(12 to convert to feet)=7.14 feet per tire revolution and the trip is 100 miles (5280 ftx100) or 528,000 ft. 528,000 ft/7.14= 73,950 tire rotations to complete the trip.
2006-11-30 03:54:50 · answer #1 · answered by BC 2 · 1⤊ 1⤋
30. it is circular, so the area of the top is pi*r^2=pi*25/4 ft. at a cost of $3 per foot, the total cost is $3*25/4*pi which is about $58.90.
38. the area of a triangle is (1/2)*b*h=(1/2)*30*20=300 ft. so the cost is $3*300=$900.
44. for this one, you need the circumference. it is 2*pi*r=2*pi*14=pi*28 in. 100 mi in inches is 5280 ft/mi * 12 in/ft * 100=63360 in/mi * 100=6336000 in. so now you divide the distance by the circumference:
6336000/(pi*28) which is about 72029 revolutions.
note: i used 3.141592654 as pi. you may need a more precise or less precise estimation, so change your estimation of pi accordingly (use 3.14 instead, for example)
2006-11-30 04:05:43 · answer #2 · answered by nemahknatut88 2 · 1⤊ 1⤋
I will help you with #38
The area of a triangle is 1/2 base X height so.....
1/2 30ft X 20 =300 sq. ft
300 sq. ft X $3 per sq. foot= $900
2006-11-30 03:57:33 · answer #3 · answered by digger 1 · 1⤊ 1⤋
30) d = 5, r = d/2, A = π * r^2, C = 3A
C = 3(π * ((5)/2)^2) ~ $58.90
38) b = 30, h = 20, A = b * h / 2, C = 3A
C = 3((30) * (20) / 2) = $900.00
1 mile = 63,360 inches
44) r = 14, D = 6,336,000, c = π * 2 * r, R = D / c
R = (6336000) / (π * 2 * (14)) ~ 72,029 revolutions
2006-11-30 04:07:42 · answer #4 · answered by bayou64 4 · 1⤊ 0⤋
I will help you with #44
circumference of circular tire = 2(pi)r = 87.9646 " (one circumference per revolution)
inches in 100 miles = 5280*12*100 = 6,336,000 "
6,336,000 " / 87.9646 " = approx. 72029 revolutions
2006-11-30 04:09:16 · answer #5 · answered by Anonymous · 0⤊ 1⤋
30. $58.93
38. $900.00
44. 144,000
2006-11-30 04:06:58 · answer #6 · answered by Toy 2 · 1⤊ 1⤋