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Finding the Fourth Proportional to 521.52, 782.36 and 391.72

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Solution

The fourth proportional to 521.52, 782.36 and 391.72 is: 587.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.52 : 782.36 = 391.72 : x
  2. Step 2: Convert to fraction form
    521.52/782.36 = 391.72/x
  3. Step 3: Cross multiply
    521.52x = 782.36 × 391.72
  4. Step 4: Simplify right side
    521.52x = 306,466.06
  5. Step 5: Solve for x
    x = 306,466.06/521.52
  6. Step 6: Final answer
    x = 587.64

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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.