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Finding the Fourth Proportional to 221.66, 305.90 and 156.30

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Solution

The fourth proportional to 221.66, 305.90 and 156.30 is: 215.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.66 : 305.90 = 156.30 : x
  2. Step 2: Convert to fraction form
    221.66/305.90 = 156.30/x
  3. Step 3: Cross multiply
    221.66x = 305.90 × 156.30
  4. Step 4: Simplify right side
    221.66x = 47,812.17
  5. Step 5: Solve for x
    x = 47,812.17/221.66
  6. Step 6: Final answer
    x = 215.70

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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.