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Finding the Fourth Proportional to 420.86, 631.40 and 147.15

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Solution

The fourth proportional to 420.86, 631.40 and 147.15 is: 220.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.86 : 631.40 = 147.15 : x
  2. Step 2: Convert to fraction form
    420.86/631.40 = 147.15/x
  3. Step 3: Cross multiply
    420.86x = 631.40 × 147.15
  4. Step 4: Simplify right side
    420.86x = 92,909.77
  5. Step 5: Solve for x
    x = 92,909.77/420.86
  6. Step 6: Final answer
    x = 220.76

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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.