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Finding the Fourth Proportional to 521.79, 781.65 and 391.93

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Solution

The fourth proportional to 521.79, 781.65 and 391.93 is: 587.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.79 : 781.65 = 391.93 : x
  2. Step 2: Convert to fraction form
    521.79/781.65 = 391.93/x
  3. Step 3: Cross multiply
    521.79x = 781.65 × 391.93
  4. Step 4: Simplify right side
    521.79x = 306,352.08
  5. Step 5: Solve for x
    x = 306,352.08/521.79
  6. Step 6: Final answer
    x = 587.12

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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.