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Finding the Fourth Proportional to 420.10, 630.24 and 214.78

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Solution

The fourth proportional to 420.10, 630.24 and 214.78 is: 322.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.10 : 630.24 = 214.78 : x
  2. Step 2: Convert to fraction form
    420.10/630.24 = 214.78/x
  3. Step 3: Cross multiply
    420.10x = 630.24 × 214.78
  4. Step 4: Simplify right side
    420.10x = 135,362.95
  5. Step 5: Solve for x
    x = 135,362.95/420.10
  6. Step 6: Final answer
    x = 322.22

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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.