| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.31 |
| Score | 0% | 66% |
Order the following types of angle from least number of degrees to most number of degrees.
acute, right, obtuse |
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right, acute, obtuse |
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acute, obtuse, right |
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right, obtuse, acute |
An acute angle measures less than 90°, a right angle measures 90°, and an obtuse angle measures more than 90°.
A(n) __________ is two expressions separated by an equal sign.
expression |
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formula |
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problem |
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equation |
An equation is two expressions separated by an equal sign. The key to solving equations is to repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.
Solve for x:
x2 + 2x - 84 = 2x - 3
| -2 or -5 | |
| -4 or -6 | |
| 9 or -9 | |
| 6 or 3 |
The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:
x2 + 2x - 84 = 2x - 3
x2 + 2x - 84 + 3 = 2x
x2 + 2x - 2x - 81 = 0
x2 - 81 = 0
Next, factor the quadratic equation:
x2 - 81 = 0
(x - 9)(x + 9) = 0
For this expression to be true, the left side of the expression must equal zero. Therefore, either (x - 9) or (x + 9) must equal zero:
If (x - 9) = 0, x must equal 9
If (x + 9) = 0, x must equal -9
So the solution is that x = 9 or -9
The dimensions of this cylinder are height (h) = 9 and radius (r) = 3. What is the surface area?
| 72π | |
| 16π | |
| 88π | |
| 84π |
The surface area of a cylinder is 2πr2 + 2πrh:
sa = 2πr2 + 2πrh
sa = 2π(32) + 2π(3 x 9)
sa = 2π(9) + 2π(27)
sa = (2 x 9)π + (2 x 27)π
sa = 18π + 54π
sa = 72π
What is 2a - 6a?
| -4 | |
| 8 | |
| 12a | |
| -4a |
To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.
2a - 6a = -4a