| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.04 |
| Score | 0% | 61% |
Simplify 6a x 3b.
| 18ab | |
| 9ab | |
| 18\( \frac{a}{b} \) | |
| 18\( \frac{b}{a} \) |
To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.
6a x 3b = (6 x 3) (a x b) = 18ab
If the area of this square is 49, what is the length of one of the diagonals?
| 3\( \sqrt{2} \) | |
| 8\( \sqrt{2} \) | |
| 4\( \sqrt{2} \) | |
| 7\( \sqrt{2} \) |
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 = \( \sqrt{a} \) = \( \sqrt{49} \) = 7
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 = 72 + 72
c2 = 98
c = \( \sqrt{98} \) = \( \sqrt{49 x 2} \) = \( \sqrt{49} \) \( \sqrt{2} \)
c = 7\( \sqrt{2} \)
A cylinder with a radius (r) and a height (h) has a surface area of:
π r2h |
|
4π r2 |
|
2(π r2) + 2π rh |
|
π r2h2 |
A cylinder is a solid figure with straight parallel sides and a circular or oval cross section with a radius (r) and a height (h). The volume of a cylinder is π r2h and the surface area is 2(π r2) + 2π rh.
The dimensions of this cylinder are height (h) = 1 and radius (r) = 6. What is the surface area?
| 36π | |
| 84π | |
| 80π | |
| 20π |
The surface area of a cylinder is 2πr2 + 2πrh:
sa = 2πr2 + 2πrh
sa = 2π(62) + 2π(6 x 1)
sa = 2π(36) + 2π(6)
sa = (2 x 36)π + (2 x 6)π
sa = 72π + 12π
sa = 84π
Solve for c:
c2 - 44 = -c - 2
| 6 or -7 | |
| 6 or -9 | |
| 2 or -1 | |
| 4 or -5 |
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:
c2 - 44 = -c - 2
c2 - 44 + 2 = -c
c2 + + c - 42 = 0
c2 + c - 42 = 0
Next, factor the quadratic equation:
c2 + c - 42 = 0
(c - 6)(c + 7) = 0
For this expression to be true, the left side of the expression must equal zero. Therefore, either (c - 6) or (c + 7) must equal zero:
If (c - 6) = 0, c must equal 6
If (c + 7) = 0, c must equal -7
So the solution is that c = 6 or -7