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Finding the Fourth Proportional to 387.59, 534.78 and 221.72

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Solution

The fourth proportional to 387.59, 534.78 and 221.72 is: 305.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.59 : 534.78 = 221.72 : x
  2. Step 2: Convert to fraction form
    387.59/534.78 = 221.72/x
  3. Step 3: Cross multiply
    387.59x = 534.78 × 221.72
  4. Step 4: Simplify right side
    387.59x = 118,568.75
  5. Step 5: Solve for x
    x = 118,568.75/387.59
  6. Step 6: Final answer
    x = 305.92

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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.