Write each formula as an English phrase using the word varies or proportional. V = 1/3 πr^2h, where V is the volume of a cone of radius r and height h
Table of contents
- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
1. Equations & Inequalities
Rational Equations
Problem 3
Textbook Question
Fill in the blank(s) to correctly complete each sentence, or answer the question as appropriate. In the equation y = 6x, y varies directly as x. When x=5, y=30. What is the value of y when x=10?
Verified step by step guidance1
Identify the type of variation described. Since y varies directly as x, the relationship can be written as \(y = kx\), where \(k\) is the constant of proportionality.
Use the given values to find the constant \(k\). Substitute \(x = 5\) and \(y = 30\) into the equation \(y = kx\) to get \$30 = k \times 5$.
Solve for \(k\) by dividing both sides of the equation by 5, resulting in \(k = \frac{30}{5}\).
Write the complete direct variation equation using the found value of \(k\), which will be \(y = kx\) with the specific \(k\) value.
Find the value of \(y\) when \(x = 10\) by substituting \(x = 10\) into the equation \(y = kx\) and calculating \(y\).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Direct Variation
Direct variation describes a relationship where one variable is a constant multiple of another. In the equation y = kx, y varies directly as x, meaning if x changes, y changes proportionally by the constant k.
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Constant of Variation
The constant of variation (k) is the fixed multiplier in a direct variation equation y = kx. It can be found by substituting known values of x and y, allowing you to determine the exact relationship between the variables.
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Substitution to Find Unknown Values
Once the constant of variation is known, substitution involves replacing the variable x with a given value to calculate the corresponding y. This method helps solve for unknowns in direct variation problems.
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