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Finding the Fourth Proportional to 420.78, 630.36 and 324.12

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Solution

The fourth proportional to 420.78, 630.36 and 324.12 is: 485.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.78 : 630.36 = 324.12 : x
  2. Step 2: Convert to fraction form
    420.78/630.36 = 324.12/x
  3. Step 3: Cross multiply
    420.78x = 630.36 × 324.12
  4. Step 4: Simplify right side
    420.78x = 204,312.28
  5. Step 5: Solve for x
    x = 204,312.28/420.78
  6. Step 6: Final answer
    x = 485.56

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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.