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Finding the Fourth Proportional to 221.28, 305.70 and 156.12

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Solution

The fourth proportional to 221.28, 305.70 and 156.12 is: 215.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.28 : 305.70 = 156.12 : x
  2. Step 2: Convert to fraction form
    221.28/305.70 = 156.12/x
  3. Step 3: Cross multiply
    221.28x = 305.70 × 156.12
  4. Step 4: Simplify right side
    221.28x = 47,725.88
  5. Step 5: Solve for x
    x = 47,725.88/221.28
  6. Step 6: Final answer
    x = 215.68

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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.