| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.96 |
| Score | 0% | 59% |
The formula for the area of a circle is which of the following?
a = π r |
|
a = π r2 |
|
a = π d2 |
|
a = π d |
The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)2 : a = π r2.
The endpoints of this line segment are at (-2, -6) and (2, 4). What is the slope-intercept equation for this line?
| y = 1\(\frac{1}{2}\)x + 3 | |
| y = 2\(\frac{1}{2}\)x - 1 | |
| y = -2x + 3 | |
| y = -2\(\frac{1}{2}\)x - 2 |
The slope-intercept equation for a line is y = mx + b where m is the slope and b is the y-intercept of the line. From the graph, you can see that the y-intercept (the y-value from the point where the line crosses the y-axis) is -1. The slope of this line is the change in y divided by the change in x. The endpoints of this line segment are at (-2, -6) and (2, 4) so the slope becomes:
m = \( \frac{\Delta y}{\Delta x} \) = \( \frac{(4.0) - (-6.0)}{(2) - (-2)} \) = \( \frac{10}{4} \)Plugging these values into the slope-intercept equation:
y = 2\(\frac{1}{2}\)x - 1
Solve for c:
-9c - 3 < 8 - 8c
| c < \(\frac{3}{4}\) | |
| c < -11 | |
| c < -2 | |
| c < -\(\frac{3}{5}\) |
To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the < sign and the answer on the other.
-9c - 3 < 8 - 8c
-9c < 8 - 8c + 3
-9c + 8c < 8 + 3
-c < 11
c < \( \frac{11}{-1} \)
c < -11
The dimensions of this trapezoid are a = 5, b = 9, c = 7, d = 3, and h = 4. What is the area?
| 25 | |
| 24 | |
| 18 | |
| 15 |
The area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:
a = ½(b + d)(h)
a = ½(9 + 3)(4)
a = ½(12)(4)
a = ½(48) = \( \frac{48}{2} \)
a = 24
What is the area of a circle with a radius of 5?
| 9π | |
| 8π | |
| 36π | |
| 25π |
The formula for area is πr2:
a = πr2
a = π(52)
a = 25π