Answer: The answer is the first explanation.
Step-by-step explanation: We are given five different options and we are to select which explanation is correct to derive the formula for a circumference of a circle.
Let 'C' be the circumference and 'd' be the diameter of a circle. Now, we will write the ratio of the circumference to the diameter as

Also, we know that

And diameter of a circle is twice the radius, so

Therefore,

This is the formula for the circumference of a circle. Since this explanation matches exactly with the first option, so the correct option is
(a). Find the relationship between the circumference and the diameter by dividing the length of the circumference and length of the diameter. Use this quotient to set up an equation to showing the ratio of the circumference over the diameter equals to π . Then rearrange the equation to solve for the circumference. Substitute 2 times the radius for the diameter.
Answer:
No
Step-by-step explanation:
No because (1,2) falls on the line, and the line is a dotted line, which means that any point on the line is not a solution to the inequality.
Answer:
Area of equilateral triangle:36cm
Square area:12cm
Step-by-step explanation:
We need to find the corresponding relationship, it is not difficult to find that this is a simple quadratic function problem.
I used pictures to express the process. You can click to view. I'm not English either. I'm Chinese, but I believe that academics know no boundaries.
Answer:
Y-intercept = -3
Step-by-step explanation:
This equation is written in Slope Intercept Form or y = mx+b Form, where b represents the y-intercept and m represents the slope of the equation.
Answer:
699.7
Step-by-step explanation:
690.95 + 8.75 = 699.7