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Finding the Fourth Proportional to 420.32, 630.39 and 142.65

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Solution

The fourth proportional to 420.32, 630.39 and 142.65 is: 213.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.32 : 630.39 = 142.65 : x
  2. Step 2: Convert to fraction form
    420.32/630.39 = 142.65/x
  3. Step 3: Cross multiply
    420.32x = 630.39 × 142.65
  4. Step 4: Simplify right side
    420.32x = 89,925.67
  5. Step 5: Solve for x
    x = 89,925.67/420.32
  6. Step 6: Final answer
    x = 213.94

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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.