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Finding the Fourth Proportional to 420.18, 578.70 and 398.22

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Solution

The fourth proportional to 420.18, 578.70 and 398.22 is: 548.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.18 : 578.70 = 398.22 : x
  2. Step 2: Convert to fraction form
    420.18/578.70 = 398.22/x
  3. Step 3: Cross multiply
    420.18x = 578.70 × 398.22
  4. Step 4: Simplify right side
    420.18x = 230,449.91
  5. Step 5: Solve for x
    x = 230,449.91/420.18
  6. Step 6: Final answer
    x = 548.46

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.