8.60 cm is the answer to your question and i used calculator.net for help
B. 2
4x + 3 = 7x - 3
7x - 4x = 3 + 3
3x = 6
x = 2
<em><u>The surface area of cylinder in standard form is:</u></em>

<em><u>Solution:</u></em>
Given that,
Radius of cylinder = 2x + 3 inches
Height of cylinder = 3 times radius = 3(2x + 3)
Height of cylinder = 6x + 9 inches
<em><u>The surface area of cylinder is given by formula:</u></em>

Where, "r" is the radius and "h" is the height of cylinder
<em><u>Substituting the given values we get,</u></em>

Thus the surface area of cylinder in standard form is found
Answer with explanation:
Since there is no information provided on what options to determine the proportional relationship, so I will be demonstrating using examples and telling the method to compare the average running speeds.
Consider a group of 3 friends named Charles, Beck and Anna.
As they wanted to compare their average running speeds, they recorded the distance and amount of time each person ran one saturday morning.
To calculate Average Speed, we use:
Average Speed = 
Example:
Charles Ran:
5 km in 30 minutes
Beck Ran :
2 km in 25 minutes
Anna Ran:
4 km in 20 minutes
Average speed of Charles = 
Average speed of Beck = 
Average speed of Anna =
<em>Here, we can see from comparison that Average running speed of Anna is the most.</em>
Speed of Beck is proportional to both Charles and Anna.
Charles' Speed =2 (Beck's Speed)
Anna's Speed =2.5 (Beck's Speed)