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Finding the Fourth Proportional to 221.90, 306.15 and 139.01

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Solution

The fourth proportional to 221.90, 306.15 and 139.01 is: 191.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.90 : 306.15 = 139.01 : x
  2. Step 2: Convert to fraction form
    221.90/306.15 = 139.01/x
  3. Step 3: Cross multiply
    221.90x = 306.15 × 139.01
  4. Step 4: Simplify right side
    221.90x = 42,556.38
  5. Step 5: Solve for x
    x = 42,556.38/221.90
  6. Step 6: Final answer
    x = 191.79

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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.