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Finding the Fourth Proportional to 861.42, 1,289.61 and 656.76

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Solution

The fourth proportional to 861.42, 1,289.61 and 656.76 is: 983.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.42 : 1,289.61 = 656.76 : x
  2. Step 2: Convert to fraction form
    861.42/1,289.61 = 656.76/x
  3. Step 3: Cross multiply
    861.42x = 1,289.61 × 656.76
  4. Step 4: Simplify right side
    861.42x = 846,964.26
  5. Step 5: Solve for x
    x = 846,964.26/861.42
  6. Step 6: Final answer
    x = 983.22

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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.