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Finding the Fourth Proportional to 861.07, 1,188.20 and 487.98

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Solution

The fourth proportional to 861.07, 1,188.20 and 487.98 is: 673.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.07 : 1,188.20 = 487.98 : x
  2. Step 2: Convert to fraction form
    861.07/1,188.20 = 487.98/x
  3. Step 3: Cross multiply
    861.07x = 1,188.20 × 487.98
  4. Step 4: Simplify right side
    861.07x = 579,817.84
  5. Step 5: Solve for x
    x = 579,817.84/861.07
  6. Step 6: Final answer
    x = 673.37

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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.