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Finding the Fourth Proportional to 521.78, 782.40 and 278.24

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Solution

The fourth proportional to 521.78, 782.40 and 278.24 is: 417.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.78 : 782.40 = 278.24 : x
  2. Step 2: Convert to fraction form
    521.78/782.40 = 278.24/x
  3. Step 3: Cross multiply
    521.78x = 782.40 × 278.24
  4. Step 4: Simplify right side
    521.78x = 217,694.98
  5. Step 5: Solve for x
    x = 217,694.98/521.78
  6. Step 6: Final answer
    x = 417.22

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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.