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Finding the Fourth Proportional to 427.92, 641.88 and 139.32

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Solution

The fourth proportional to 427.92, 641.88 and 139.32 is: 208.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.92 : 641.88 = 139.32 : x
  2. Step 2: Convert to fraction form
    427.92/641.88 = 139.32/x
  3. Step 3: Cross multiply
    427.92x = 641.88 × 139.32
  4. Step 4: Simplify right side
    427.92x = 89,426.72
  5. Step 5: Solve for x
    x = 89,426.72/427.92
  6. Step 6: Final answer
    x = 208.98

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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.