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Finding the Fourth Proportional to 861.60, 1,290.24 and 687.52

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Solution

The fourth proportional to 861.60, 1,290.24 and 687.52 is: 1,029.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.60 : 1,290.24 = 687.52 : x
  2. Step 2: Convert to fraction form
    861.60/1,290.24 = 687.52/x
  3. Step 3: Cross multiply
    861.60x = 1,290.24 × 687.52
  4. Step 4: Simplify right side
    861.60x = 887,065.80
  5. Step 5: Solve for x
    x = 887,065.80/861.60
  6. Step 6: Final answer
    x = 1,029.56

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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.