| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.71 |
| Score | 0% | 54% |
If the area of this square is 25, what is the length of one of the diagonals?
| 3\( \sqrt{2} \) | |
| 5\( \sqrt{2} \) | |
| 4\( \sqrt{2} \) | |
| 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 = \( \sqrt{a} \) = \( \sqrt{25} \) = 5
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 = 52 + 52
c2 = 50
c = \( \sqrt{50} \) = \( \sqrt{25 x 2} \) = \( \sqrt{25} \) \( \sqrt{2} \)
c = 5\( \sqrt{2} \)
What is the circumference of a circle with a radius of 11?
| 22π | |
| 12π | |
| 8π | |
| 6π |
The formula for circumference is circle diameter x π. Circle diameter is 2 x radius:
c = πd
c = π(2 * r)
c = π(2 * 11)
c = 22π
When two lines intersect, adjacent angles are __________ (they add up to 180°) and angles across from either other are __________ (they're equal).
supplementary, vertical |
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acute, obtuse |
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vertical, supplementary |
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obtuse, acute |
Angles around a line add up to 180°. Angles around a point add up to 360°. When two lines intersect, adjacent angles are supplementary (they add up to 180°) and angles across from either other are vertical (they're equal).
The endpoints of this line segment are at (-2, -1) and (2, 7). What is the slope of this line?
| -\(\frac{1}{2}\) | |
| 2 | |
| -1 | |
| 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, -1) and (2, 7) so the slope becomes:
m = \( \frac{\Delta y}{\Delta x} \) = \( \frac{(7.0) - (-1.0)}{(2) - (-2)} \) = \( \frac{8}{4} \)The formula for the area of a circle is which of the following?
c = π r2 |
|
c = π r |
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c = π d |
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c = π d2 |
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.