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Finding the Fourth Proportional to 389.77, 537.84 and 221.72

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Solution

The fourth proportional to 389.77, 537.84 and 221.72 is: 305.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.77 : 537.84 = 221.72 : x
  2. Step 2: Convert to fraction form
    389.77/537.84 = 221.72/x
  3. Step 3: Cross multiply
    389.77x = 537.84 × 221.72
  4. Step 4: Simplify right side
    389.77x = 119,249.88
  5. Step 5: Solve for x
    x = 119,249.88/389.77
  6. Step 6: Final answer
    x = 305.95

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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.