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Finding the Fourth Proportional to 861.90, 1,193.31 and 818.70

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Solution

The fourth proportional to 861.90, 1,193.31 and 818.70 is: 1,133.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.90 : 1,193.31 = 818.70 : x
  2. Step 2: Convert to fraction form
    861.90/1,193.31 = 818.70/x
  3. Step 3: Cross multiply
    861.90x = 1,193.31 × 818.70
  4. Step 4: Simplify right side
    861.90x = 976,962.90
  5. Step 5: Solve for x
    x = 976,962.90/861.90
  6. Step 6: Final answer
    x = 1,133.50

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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.