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Finding the Fourth Proportional to 908.31, 1,362.24 and 420.90

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Solution

The fourth proportional to 908.31, 1,362.24 and 420.90 is: 631.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    908.31 : 1,362.24 = 420.90 : x
  2. Step 2: Convert to fraction form
    908.31/1,362.24 = 420.90/x
  3. Step 3: Cross multiply
    908.31x = 1,362.24 × 420.90
  4. Step 4: Simplify right side
    908.31x = 573,366.82
  5. Step 5: Solve for x
    x = 573,366.82/908.31
  6. Step 6: Final answer
    x = 631.25

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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.