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Finding the Fourth Proportional to 778.40, 1,167.20 and 291.28

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Solution

The fourth proportional to 778.40, 1,167.20 and 291.28 is: 436.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.40 : 1,167.20 = 291.28 : x
  2. Step 2: Convert to fraction form
    778.40/1,167.20 = 291.28/x
  3. Step 3: Cross multiply
    778.40x = 1,167.20 × 291.28
  4. Step 4: Simplify right side
    778.40x = 339,982.02
  5. Step 5: Solve for x
    x = 339,982.02/778.40
  6. Step 6: Final answer
    x = 436.77

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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.