The first term of a linear sequence is 3 and the 18th term is 31. Find the common difference
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Answer:
<u><em>6</em></u> rolls because the total perimeter is 102 ft and five rolls is only 100 feet. So she needs <em><u>6</u></em> rolls.
Step-by-step explanation:
to find perimeter, add up all the side lengths.
so 15*4 (it's easier than 15+15+15...)
60 ft.
now we have to use Pythagorean's Theorum to find corner to corner.
so
we have a and b
do the math...
225+225= 450
square root of 450=
21.213
double that because it's used twice (corner to corner and corner to corner)
42.426
now add it all up
42.426 + 60 = 102.426
we can round
102
20*5 = 100
so she needs 6
MY ORIGINAL ERROR WAS 5, BUT 5 TIMES 20 IS ONLY 80, SO THEREFORE 6 IS REQUIRED SO THERE IS ENOUGH TO COVER 102.
We effectively rewrite the equation as
In order for the LHS to be defined, we need to restrict , or
. Now, the LHS will vanish when the numerator is 0, which happens for
This value is indeed smaller than 4, so the solution is .