Melinda and Paul shovel driveways and sidewalks in the winter as a way to earn extra money. Together they shoveled 450 square fe
1 answer:
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Answer:
C
Step-by-step explanation:
Calculate AC using Pythagoras' identity in ΔABC
AC² = 20² - 12² = 400 - 144 = 256, hence
AC = = 16
Now find AD² from ΔACD and ΔABD
ΔACD → AD² = 16² - (20 - x)² = 256 - 400 + 40x - x²
ΔABD → AD² = 12² - x² = 144 - x²
Equate both equations for AD², hence
256 - 400 + 40x - x² = 144 - x²
-144 + 40x - x² = 144 - x² ( add x² to both sides )
- 144 + 40x = 144 ( add 144 to both sides )
40x = 288 ( divide both sides by 40 )
x = 7.2 → C
Answer:
The result is the same.
Step-by-step explanation:
I think your question is missed of key information, allow me to add in and hope it will fit the original one.
Please have a look at the attached photo.
My answer:
Given the information:
- square 12 inches wide
- 3-inch diameter cookies are cut => its radius is: 1.5 inches
Hence we can find some information:
- The area of the square is:
square inches
- The area of a cookies is:
π = 3.14*
= 7.065 square inches
- The total number of 3-inch cookies are: 4*4 =16
=> The total area of the cookies is: 16* 7.065 = 113.04 square inches
=> how much cookie dough is "wasted" when 3-inch cookies are cut:
= The area of the square - The total area of the cookies
= 144 - 113.04 = 30.96 square inches
If the diameter is increased to 4 inches => its radius: 2 inches, we have:
- The area of a cookies is:
square inches
- The total number of 3-inch cookies are: 3*3 =9
=> The total area of the cookies is: 9* 12.56 = 113.04 square inches
=> how much cookie dough is "wasted" when 4-inch cookies are cut:
= The area of the square - The total area of the cookies
= 144 - 113.04 = 30.96 square inches
The result is the same.
