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Finding the Fourth Proportional to 492.42, 678.31 and 398.91

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Solution

The fourth proportional to 492.42, 678.31 and 398.91 is: 549.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    492.42 : 678.31 = 398.91 : x
  2. Step 2: Convert to fraction form
    492.42/678.31 = 398.91/x
  3. Step 3: Cross multiply
    492.42x = 678.31 × 398.91
  4. Step 4: Simplify right side
    492.42x = 270,584.62
  5. Step 5: Solve for x
    x = 270,584.62/492.42
  6. Step 6: Final answer
    x = 549.50

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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.