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Finding the Fourth Proportional to 420.62, 630.97 and 128.15

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Solution

The fourth proportional to 420.62, 630.97 and 128.15 is: 192.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.62 : 630.97 = 128.15 : x
  2. Step 2: Convert to fraction form
    420.62/630.97 = 128.15/x
  3. Step 3: Cross multiply
    420.62x = 630.97 × 128.15
  4. Step 4: Simplify right side
    420.62x = 80,855.01
  5. Step 5: Solve for x
    x = 80,855.01/420.62
  6. Step 6: Final answer
    x = 192.23

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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.