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Finding the Fourth Proportional to 221.18, 305.12 and 155.72

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Solution

The fourth proportional to 221.18, 305.12 and 155.72 is: 214.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.18 : 305.12 = 155.72 : x
  2. Step 2: Convert to fraction form
    221.18/305.12 = 155.72/x
  3. Step 3: Cross multiply
    221.18x = 305.12 × 155.72
  4. Step 4: Simplify right side
    221.18x = 47,513.29
  5. Step 5: Solve for x
    x = 47,513.29/221.18
  6. Step 6: Final answer
    x = 214.82

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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.