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Finding the Fourth Proportional to 390.78, 586.16 and 113.14

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Solution

The fourth proportional to 390.78, 586.16 and 113.14 is: 169.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.78 : 586.16 = 113.14 : x
  2. Step 2: Convert to fraction form
    390.78/586.16 = 113.14/x
  3. Step 3: Cross multiply
    390.78x = 586.16 × 113.14
  4. Step 4: Simplify right side
    390.78x = 66,318.14
  5. Step 5: Solve for x
    x = 66,318.14/390.78
  6. Step 6: Final answer
    x = 169.71

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.