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Finding the Fourth Proportional to 674.90, 1,011.28 and 521.20

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Solution

The fourth proportional to 674.90, 1,011.28 and 521.20 is: 780.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    674.90 : 1,011.28 = 521.20 : x
  2. Step 2: Convert to fraction form
    674.90/1,011.28 = 521.20/x
  3. Step 3: Cross multiply
    674.90x = 1,011.28 × 521.20
  4. Step 4: Simplify right side
    674.90x = 527,079.14
  5. Step 5: Solve for x
    x = 527,079.14/674.90
  6. Step 6: Final answer
    x = 780.97

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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.