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Finding the Fourth Proportional to 221.28, 305.28 and 138.48

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Solution

The fourth proportional to 221.28, 305.28 and 138.48 is: 191.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.28 : 305.28 = 138.48 : x
  2. Step 2: Convert to fraction form
    221.28/305.28 = 138.48/x
  3. Step 3: Cross multiply
    221.28x = 305.28 × 138.48
  4. Step 4: Simplify right side
    221.28x = 42,275.17
  5. Step 5: Solve for x
    x = 42,275.17/221.28
  6. Step 6: Final answer
    x = 191.05

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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.