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Finding the Fourth Proportional to 869.30, 1,305.15 and 686.90

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Solution

The fourth proportional to 869.30, 1,305.15 and 686.90 is: 1,031.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.30 : 1,305.15 = 686.90 : x
  2. Step 2: Convert to fraction form
    869.30/1,305.15 = 686.90/x
  3. Step 3: Cross multiply
    869.30x = 1,305.15 × 686.90
  4. Step 4: Simplify right side
    869.30x = 896,507.54
  5. Step 5: Solve for x
    x = 896,507.54/869.30
  6. Step 6: Final answer
    x = 1,031.30

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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.