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Finding the Fourth Proportional to 861.84, 1,286.89 and 813.11

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Solution

The fourth proportional to 861.84, 1,286.89 and 813.11 is: 1,214.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.84 : 1,286.89 = 813.11 : x
  2. Step 2: Convert to fraction form
    861.84/1,286.89 = 813.11/x
  3. Step 3: Cross multiply
    861.84x = 1,286.89 × 813.11
  4. Step 4: Simplify right side
    861.84x = 1,046,383.13
  5. Step 5: Solve for x
    x = 1,046,383.13/861.84
  6. Step 6: Final answer
    x = 1,214.13

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.