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Finding the Fourth Proportional to 420.85, 630.99 and 215.02

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Solution

The fourth proportional to 420.85, 630.99 and 215.02 is: 322.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.85 : 630.99 = 215.02 : x
  2. Step 2: Convert to fraction form
    420.85/630.99 = 215.02/x
  3. Step 3: Cross multiply
    420.85x = 630.99 × 215.02
  4. Step 4: Simplify right side
    420.85x = 135,675.47
  5. Step 5: Solve for x
    x = 135,675.47/420.85
  6. Step 6: Final answer
    x = 322.38

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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.