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Finding the Fourth Proportional to 1,209.86, 1,812.39 and 688.29

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Solution

The fourth proportional to 1,209.86, 1,812.39 and 688.29 is: 1,031.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.86 : 1,812.39 = 688.29 : x
  2. Step 2: Convert to fraction form
    1,209.86/1,812.39 = 688.29/x
  3. Step 3: Cross multiply
    1,209.86x = 1,812.39 × 688.29
  4. Step 4: Simplify right side
    1,209.86x = 1,247,449.91
  5. Step 5: Solve for x
    x = 1,247,449.91/1,209.86
  6. Step 6: Final answer
    x = 1,031.07

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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.