The number of rows in the arena is 26
<h3>How to determine the number of rows?</h3>
The hockey arena illustrates an arithmetic sequence, and it has the following parameters:
- First term, a = 220
- Sum of terms, Sn = 10920
- Common difference, d = 16
The number of rows (i.e. the number of terms) is calculated using:
So,we have:
Evaluate the terms and factors
Evaluate the like terms
21840 = n(424+ 16n)
Expand
21840 = 424n + 16n^2
Rewrite as:
16n^2 + 424n - 21840 = 0
Using a graphical tool, we have:
n = 26
Hence, the number of rows in the arena is 26
Read more about arithmetic sequence at:
brainly.com/question/6561461
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The sample size should be 250.
Our margin of error is 4%, or 0.04. We use the formula
To find the z-score:
Convert 98% to a decimal: 0.98
Subtract from 1: 1-0.98 = 0.02
Divide both sides by 2: 0.02/2 = 0.01
Subtract from 1: 1-0.01 = 0.99
Using a z-table (http://www.z-table.com) we see that this value has a z-score of approximately 2.33. Using this, our margin of error and our proportion, we have:
Divide both sides by 2.33:
Square both sides:
Multiply both sides by n:
Divide both sides to isolate n:
Answer:
The height of the triangle is 7cm and the base is 16cm
Step-by-step explanation:
First of all we have to know the formula to calculate area of a triangle
a = area = 56
b = base
h = heigth
a = (b * h)/2
we replace the known values and we make 2 equations
56cm² = (b * h)/2
b = h + 9cm
we replace b by (h + 9cm) in the first equation
56cm² = (h + 9cm * h)/2
56cm² * 2 = h² + 9h
0 = h² + 9h - 112cm²
we use bhaskara formula:
(-b (±) √
(b² - 4ac) ) / 2a
we replace with the known values
h = (-9 (±) √
(9² - 4*1*(-112) ) ) / 2*1
h = (-9 (±) √
(81 + 448) ) ) / 2
h = (-9 (±) √529) /2
h = (-9 (±) 23)/2
h1 = (-9 + 23) / 2
h1 = 14 / 2
h1 = 7
h2 = (-9 - 23) / 2
h2 = -32 / 2
h2 = -16
The height of the triangle is 7cm and the base is 16cm
Answer:
1.) Increase
2.) Decrease
3.) Increase
4.) Decrease
