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Finding the Fourth Proportional to 420.42, 630.64 and 131.88

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Solution

The fourth proportional to 420.42, 630.64 and 131.88 is: 197.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.42 : 630.64 = 131.88 : x
  2. Step 2: Convert to fraction form
    420.42/630.64 = 131.88/x
  3. Step 3: Cross multiply
    420.42x = 630.64 × 131.88
  4. Step 4: Simplify right side
    420.42x = 83,168.80
  5. Step 5: Solve for x
    x = 83,168.80/420.42
  6. Step 6: Final answer
    x = 197.82

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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.