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Finding the Fourth Proportional to 686.65, 1,029.87 and 253.70

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Solution

The fourth proportional to 686.65, 1,029.87 and 253.70 is: 380.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.65 : 1,029.87 = 253.70 : x
  2. Step 2: Convert to fraction form
    686.65/1,029.87 = 253.70/x
  3. Step 3: Cross multiply
    686.65x = 1,029.87 × 253.70
  4. Step 4: Simplify right side
    686.65x = 261,278.02
  5. Step 5: Solve for x
    x = 261,278.02/686.65
  6. Step 6: Final answer
    x = 380.51

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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.