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Finding the Fourth Proportional to 221.50, 305.40 and 138.46

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Solution

The fourth proportional to 221.50, 305.40 and 138.46 is: 190.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.50 : 305.40 = 138.46 : x
  2. Step 2: Convert to fraction form
    221.50/305.40 = 138.46/x
  3. Step 3: Cross multiply
    221.50x = 305.40 × 138.46
  4. Step 4: Simplify right side
    221.50x = 42,285.68
  5. Step 5: Solve for x
    x = 42,285.68/221.50
  6. Step 6: Final answer
    x = 190.91

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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.