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Finding the Fourth Proportional to 221.90, 306.42 and 139.15

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Solution

The fourth proportional to 221.90, 306.42 and 139.15 is: 192.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.90 : 306.42 = 139.15 : x
  2. Step 2: Convert to fraction form
    221.90/306.42 = 139.15/x
  3. Step 3: Cross multiply
    221.90x = 306.42 × 139.15
  4. Step 4: Simplify right side
    221.90x = 42,638.00
  5. Step 5: Solve for x
    x = 42,638.00/221.90
  6. Step 6: Final answer
    x = 192.15

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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.