Rounding is simple:
- If the previous digit is 5-9, round the number to the left of it up a number. If it is 4-0, leave the number to the left of it as it is.
For 82.98, we can round 82 to 83, since 82 is the whole number and the previous digit is 9 (so we round up).
For 169.645, we scratch off 45. Since 6 is in the tenth's place and the previous digit of it is 4, we leave it at 169.64.
:)
Since the base is 3 inches and the height is 4 inches, as well as the area of a triangle being base*height/2, we get 3*4/2=6 in. for each triangle. Since we need 20 pieces for each puzzle, we multiply 6 by 20 to get 120. In addition, since 80 puzzles are needed, with 20 pieces for each puzzle, we have 120 inches for each puzzle and 120*80 = 9600 square inches of wood used
Answer: about 22 minutes
Explanation: its hard to explain but trust me i checked my work
add the two equations together
5a+5b=25
-5a+5b=35
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0 + 10b =60
divide by 10
b=6
5a + 5b = 25
5a +5(6) = 25
5a +30 =25
subtract 30 from each side
5a =-5
divide by 5
a = -1
Answer (-1,6)
or a=-1 b=6
