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Finding the Fourth Proportional to 861.61, 1,187.71 and 710.40

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Solution

The fourth proportional to 861.61, 1,187.71 and 710.40 is: 979.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.61 : 1,187.71 = 710.40 : x
  2. Step 2: Convert to fraction form
    861.61/1,187.71 = 710.40/x
  3. Step 3: Cross multiply
    861.61x = 1,187.71 × 710.40
  4. Step 4: Simplify right side
    861.61x = 843,745.84
  5. Step 5: Solve for x
    x = 843,745.84/861.61
  6. Step 6: Final answer
    x = 979.26

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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.