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Finding the Fourth Proportional to 420.31, 630.43 and 131.74

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Solution

The fourth proportional to 420.31, 630.43 and 131.74 is: 197.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.31 : 630.43 = 131.74 : x
  2. Step 2: Convert to fraction form
    420.31/630.43 = 131.74/x
  3. Step 3: Cross multiply
    420.31x = 630.43 × 131.74
  4. Step 4: Simplify right side
    420.31x = 83,055.23
  5. Step 5: Solve for x
    x = 83,055.23/420.31
  6. Step 6: Final answer
    x = 197.61

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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.