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Finding the Fourth Proportional to 389.77, 537.87 and 221.70

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Solution

The fourth proportional to 389.77, 537.87 and 221.70 is: 305.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.77 : 537.87 = 221.70 : x
  2. Step 2: Convert to fraction form
    389.77/537.87 = 221.70/x
  3. Step 3: Cross multiply
    389.77x = 537.87 × 221.70
  4. Step 4: Simplify right side
    389.77x = 119,245.78
  5. Step 5: Solve for x
    x = 119,245.78/389.77
  6. Step 6: Final answer
    x = 305.94

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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.