| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.82 |
| Score | 0% | 56% |
The endpoints of this line segment are at (-2, 5) and (2, 3). What is the slope-intercept equation for this line?
| y = -3x - 4 | |
| y = -\(\frac{1}{2}\)x + 4 | |
| y = -x - 1 | |
| y = x - 3 |
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 4. 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, 5) and (2, 3) so the slope becomes:
m = \( \frac{\Delta y}{\Delta x} \) = \( \frac{(3.0) - (5.0)}{(2) - (-2)} \) = \( \frac{-2}{4} \)Plugging these values into the slope-intercept equation:
y = -\(\frac{1}{2}\)x + 4
Solve for y:
-4y + 9 > -1 + 2y
| y > 1\(\frac{1}{3}\) | |
| y > 1\(\frac{2}{3}\) | |
| y > \(\frac{5}{8}\) | |
| y > 1 |
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.
-4y + 9 > -1 + 2y
-4y > -1 + 2y - 9
-4y - 2y > -1 - 9
-6y > -10
y > \( \frac{-10}{-6} \)
y > 1\(\frac{2}{3}\)
The dimensions of this cylinder are height (h) = 1 and radius (r) = 8. What is the surface area?
| 24π | |
| 70π | |
| 12π | |
| 144π |
The surface area of a cylinder is 2πr2 + 2πrh:
sa = 2πr2 + 2πrh
sa = 2π(82) + 2π(8 x 1)
sa = 2π(64) + 2π(8)
sa = (2 x 64)π + (2 x 8)π
sa = 128π + 16π
sa = 144π
What is the area of a circle with a radius of 2?
| 4π | |
| 25π | |
| 49π | |
| 6π |
The formula for area is πr2:
a = πr2
a = π(22)
a = 4π
If the area of this square is 16, what is the length of one of the diagonals?
| 7\( \sqrt{2} \) | |
| 2\( \sqrt{2} \) | |
| 4\( \sqrt{2} \) | |
| 5\( \sqrt{2} \) |
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 = \( \sqrt{a} \) = \( \sqrt{16} \) = 4
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 = 42 + 42
c2 = 32
c = \( \sqrt{32} \) = \( \sqrt{16 x 2} \) = \( \sqrt{16} \) \( \sqrt{2} \)
c = 4\( \sqrt{2} \)