Answer:
x = 6
Step-by-step explanation:
Let x = first number
x+4x = 30
5x = 30
Divide by 5
5x/5 =30/5
x = 6
2238 - 300 = 1938 ft is your answer
<h3>
Answer: 375</h3>
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Work Shown:
a = 300 = first term
r = 60/300 = 0.2 = common ratio
We multiply each term by 0.2, aka 1/5, to get the next term.
Since -1 < r < 1 is true, we can use the infinite geometric sum formula below
S = a/(1-r)
S = 300/(1-0.2)
S = 300/0.8
S = 375
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As a sort of "check", we can add up partial sums like so
- 300+60 = 360
- 300+60+12 = 360+12 = 372
- 300+60+12+2.4 = 372+2.4 = 374.4
- 300+60+12+2.4+0.48 = 374.4+0.48 = 374.88
and so on. The idea is that each time we add on a new term, we should be getting closer and closer to 375. I put "check" in quotation marks because it's probably not the rigorous of checks possible. But it may give a good idea of what's going on.
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Side note: If the common ratio r was either r < -1 or r > 1, then the terms we add on would get larger and larger. This would mean we don't approach a single finite value with the infinite sum.
Area of a triangle:
A (triangle )= 4 · 6 / 2 = 12 ft²
150 - 12 = 138 ft² ( the maximum area of the rectangle )
L = ?
W = 6 ft
A ( rectangle ) = L · W
L · 6 = 138
L = 138 : 6 = 23 ft.
Answer: the maximum length of the base of the rectangle he can build is 23 ft.