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Finding the Fourth Proportional to 221.80, 306.07 and 128.53

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Solution

The fourth proportional to 221.80, 306.07 and 128.53 is: 177.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.80 : 306.07 = 128.53 : x
  2. Step 2: Convert to fraction form
    221.80/306.07 = 128.53/x
  3. Step 3: Cross multiply
    221.80x = 306.07 × 128.53
  4. Step 4: Simplify right side
    221.80x = 39,339.18
  5. Step 5: Solve for x
    x = 39,339.18/221.80
  6. Step 6: Final answer
    x = 177.36

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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.