Kirsten needed to paint the floor of her circular room. she started working from oustside and gradually moved towards the center of the room. she has used a gallon of paint and has paited only a 2 foot wide strip around the outside of the room. If the diameter of teh entire room is 20 feet, how many more gallons of paint will she need to buy? Could u please support it with work
2006-11-27 12:10:37 · 3 answers · asked by cutiepie_shay8 1 in Science & Mathematics ➔ Mathematics
The total area of the room is Pi * Radius squared so
3.14159*10*10=314.159 ft sq
The area of the sofar non painted part is Pi * (Radius -2)squared
3.14*8*8= 201.062
314.159-201.062=113.097
so you can pain 113.097 sq ft per gallon
314.159/113.097=2.77777
So to paint the room you need a total of 3 gallons. With one already used you need 2 more.
I hope this helps.
2006-11-27 12:25:03 · answer #1 · answered by ak_man33 3 · 0⤊ 0⤋
The radius of the room is 10 feet, so the area comes out to be around 314 square feet. Kristen has painted 2 feet wide strip with 1 gallon of paint. The area left behind is 200 sqaure feet.
She has painted 114 square feet with one gallon, and for remaining 200 feet, she will require 1.75 gallons.
2006-11-27 20:30:05 · answer #2 · answered by Hafeez 3 · 0⤊ 0⤋
Total area of room = Ï r² = Ï*10² = 314 ft²
Area she's painted = Ï(10² - 8²) = 113 ft²
So, she's painting 113 ft² / gal and needs to paint (314-113) = 201 more sq ft;
(201 ft²)/(113 ft²/gal) = 1.79 gal more
2006-11-27 20:29:55 · answer #3 · answered by Steve 7 · 0⤊ 0⤋