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Finding the Fourth Proportional to 521.78, 720 and 288.86

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Solution

The fourth proportional to 521.78, 720 and 288.86 is: 398.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.78 : 720 = 288.86 : x
  2. Step 2: Convert to fraction form
    521.78/720 = 288.86/x
  3. Step 3: Cross multiply
    521.78x = 720 × 288.86
  4. Step 4: Simplify right side
    521.78x = 207,979.20
  5. Step 5: Solve for x
    x = 207,979.20/521.78
  6. Step 6: Final answer
    x = 398.60

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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.