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Finding the Fourth Proportional to 908.78, 1,362.69 and 421.41

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Solution

The fourth proportional to 908.78, 1,362.69 and 421.41 is: 631.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    908.78 : 1,362.69 = 421.41 : x
  2. Step 2: Convert to fraction form
    908.78/1,362.69 = 421.41/x
  3. Step 3: Cross multiply
    908.78x = 1,362.69 × 421.41
  4. Step 4: Simplify right side
    908.78x = 574,251.19
  5. Step 5: Solve for x
    x = 574,251.19/908.78
  6. Step 6: Final answer
    x = 631.90

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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.