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Finding the Fourth Proportional to 765.46, 1,147.78 and 278.31

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Solution

The fourth proportional to 765.46, 1,147.78 and 278.31 is: 417.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    765.46 : 1,147.78 = 278.31 : x
  2. Step 2: Convert to fraction form
    765.46/1,147.78 = 278.31/x
  3. Step 3: Cross multiply
    765.46x = 1,147.78 × 278.31
  4. Step 4: Simplify right side
    765.46x = 319,438.65
  5. Step 5: Solve for x
    x = 319,438.65/765.46
  6. Step 6: Final answer
    x = 417.32

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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.