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Finding the Fourth Proportional to 309.12, 425.92 and 221.76

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Solution

The fourth proportional to 309.12, 425.92 and 221.76 is: 305.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.12 : 425.92 = 221.76 : x
  2. Step 2: Convert to fraction form
    309.12/425.92 = 221.76/x
  3. Step 3: Cross multiply
    309.12x = 425.92 × 221.76
  4. Step 4: Simplify right side
    309.12x = 94,452.02
  5. Step 5: Solve for x
    x = 94,452.02/309.12
  6. Step 6: Final answer
    x = 305.55

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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.