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Finding the Fourth Proportional to 861.50, 1,290.45 and 551.78

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Solution

The fourth proportional to 861.50, 1,290.45 and 551.78 is: 826.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.50 : 1,290.45 = 551.78 : x
  2. Step 2: Convert to fraction form
    861.50/1,290.45 = 551.78/x
  3. Step 3: Cross multiply
    861.50x = 1,290.45 × 551.78
  4. Step 4: Simplify right side
    861.50x = 712,044.50
  5. Step 5: Solve for x
    x = 712,044.50/861.50
  6. Step 6: Final answer
    x = 826.52

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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.