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Finding the Fourth Proportional to 501.61, 691.90 and 391.05

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Solution

The fourth proportional to 501.61, 691.90 and 391.05 is: 539.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    501.61 : 691.90 = 391.05 : x
  2. Step 2: Convert to fraction form
    501.61/691.90 = 391.05/x
  3. Step 3: Cross multiply
    501.61x = 691.90 × 391.05
  4. Step 4: Simplify right side
    501.61x = 270,567.50
  5. Step 5: Solve for x
    x = 270,567.50/501.61
  6. Step 6: Final answer
    x = 539.40

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.