Your Results | Global Average | |
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Questions | 5 | 5 |
Correct | 0 | 2.38 |
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The formula for the area of a circle is which of the following?
c = π d |
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c = π d2 |
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c = π r |
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c = π r2 |
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.
If the area of this square is 9, what is the length of one of the diagonals?
3\( \sqrt{2} \) | |
7\( \sqrt{2} \) | |
5\( \sqrt{2} \) | |
2\( \sqrt{2} \) |
To find the diagonal we need to know the length of one of the square's sides. We know the area and the area of a square is the length of one side squared:
a = s2
so the length of one side of the square is:
s = \( \sqrt{a} \) = \( \sqrt{9} \) = 3
The Pythagorean theorem defines the square of the hypotenuse (diagonal) of a triangle with a right angle as the sum of the squares of the other two sides:
c2 = a2 + b2
c2 = 32 + 32
c2 = 18
c = \( \sqrt{18} \) = \( \sqrt{9 x 2} \) = \( \sqrt{9} \) \( \sqrt{2} \)
c = 3\( \sqrt{2} \)
If the length of AB equals the length of BD, point B __________ this line segment.
midpoints |
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bisects |
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intersects |
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trisects |
A line segment is a portion of a line with a measurable length. The midpoint of a line segment is the point exactly halfway between the endpoints. The midpoint bisects (cuts in half) the line segment.
The endpoints of this line segment are at (-2, 7) and (2, -5). What is the slope-intercept equation for this line?
y = -3x + 1 | |
y = -1\(\frac{1}{2}\)x - 1 | |
y = 3x - 1 | |
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, 7) and (2, -5) so the slope becomes:
m = \( \frac{\Delta y}{\Delta x} \) = \( \frac{(-5.0) - (7.0)}{(2) - (-2)} \) = \( \frac{-12}{4} \)Plugging these values into the slope-intercept equation:
y = -3x + 1
Solve for z:
z2 + 9z + 14 = 0
9 or -6 | |
7 or -8 | |
-2 or -7 | |
3 or -3 |
The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:
z2 + 9z + 14 = 0
(z + 2)(z + 7) = 0
For this expression to be true, the left side of the expression must equal zero. Therefore, either (z + 2) or (z + 7) must equal zero:
If (z + 2) = 0, z must equal -2
If (z + 7) = 0, z must equal -7
So the solution is that z = -2 or -7