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Finding the Fourth Proportional to 427.70, 641.40 and 139.06

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Solution

The fourth proportional to 427.70, 641.40 and 139.06 is: 208.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.70 : 641.40 = 139.06 : x
  2. Step 2: Convert to fraction form
    427.70/641.40 = 139.06/x
  3. Step 3: Cross multiply
    427.70x = 641.40 × 139.06
  4. Step 4: Simplify right side
    427.70x = 89,193.08
  5. Step 5: Solve for x
    x = 89,193.08/427.70
  6. Step 6: Final answer
    x = 208.54

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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.