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Finding the Fourth Proportional to 1,281, 1,767.78 and 729

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Solution

The fourth proportional to 1,281, 1,767.78 and 729 is: 1,006.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281 : 1,767.78 = 729 : x
  2. Step 2: Convert to fraction form
    1,281/1,767.78 = 729/x
  3. Step 3: Cross multiply
    1,281x = 1,767.78 × 729
  4. Step 4: Simplify right side
    1,281x = 1,288,711.62
  5. Step 5: Solve for x
    x = 1,288,711.62/1,281
  6. Step 6: Final answer
    x = 1,006.02

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.