Answer:
y = 8x + 25
Step-by-step explanation:
Using the coordinates (10, 105) and (20, 185)
The standard linear equation is expressed as y = mx+c
m is the slope
c is the intercept
m = 185 - 105/20-10
m = 80/10
m = 8
Get the y-intercept
Since y = mx+c
105 = 8(10) + c
105 = 80 + c
c = 105 - 80
c = 25
Get the required equation
Recall that y = mx+c
y = 8x + 25
Hence the required equation is y = 8x + 25
⓵ To calculate the volume of a right circular cylinder, the formula is π times the radius of the circular base² time the height of the cylinder.
⓶ Now that we know that the equation to calculate the volume of a right circular cylinder is :
V = π x (r²) x h
You need to find the numbers to replace the volume (V) and the height (h) in the formula.
We already know that the volume is 320 square feet and that the height is 20 feet.
So we are left with a formula looking like this :
320 = π x (r²) x 20
⓷ Now we need to find the radius of the circular base! To do so, you need to solve this equation and isolate the “r”. Start by simplifying the right side :
320 = π x (r²) x 20
÷20 ÷20
↓
16 = π x r²
÷π ÷π
↓
5,09 ⋍ r²
√ √
↓
2,26 feet ⋍ r
⓸ Now that we knoe the value of the radius of the circular base, all there’s left to do is multiply this number by two in order to find the diameter of the water tank :
2,26 x 2 = d
↓
4,51 feet ⋍ d
So your final answer is : the diameter of the water tank is about 4,51 feet.
** Since I devided by “π”, all the answers I wrote from that point are rounded to the nearest hundredths just to make things easier to visualize, but I kept all of the decimals when doing the calculations. So it is possible that your answer might differ slightly from mine if you use the rounded numbers to calculate everything. Just keep that in mind!
I hope this helped, if there’s anything just let me know! ☻
Answer:
the common ratio is either 2 or -2.
the sum of the first 7 terms is then either 765 or 255
Step-by-step explanation:
a geometric sequence or series of progression (these are the most common names for the same thing) means that every new term of the sequence is created by multiplying the previous term by a constant factor which is called the common ratio.
so,
a1
a2 = a1×f
a3 = a2×f = a1×f²
a4 = a3×f = a1×f³
the problem description here tells us
a3 = 4×a1
and from above we know a3 = a1×f².
so, f² = 4
and therefore the common ratio = f = 2 or -2 (we need to keep that in mind).
again, the problem description tells us
a2 + a4 = 30
a1×f + a1×f³ = 30
for f = 2
a1×2 + a1×2³ = 30
2a1 + 8a1 = 30
10a1 = 30
a1 = 3
for f = -2
a1×-2 + a1×(-2)³ = 30
-10a1 = 30
a1 = -3
the sum of the first n terms of a geometric sequence is
sn = a1×(1 - f^(n+1))/(1-f) for f <>1
so, for f = 2
s7 = 3×(1 - 2⁸)/(1-2) = 3×-255/-1 = 3×255 = 765
for f = -2
s7 = -3×(1 - (-2)⁸)/(1 - -2) = -3×(1-256)/3 = -3×-255/3 =
= -1×-255 = 255
The equation r = u/st is equivalent to u = rst .
True
