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Finding the Fourth Proportional to 387.39, 534.56 and 221.57

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Solution

The fourth proportional to 387.39, 534.56 and 221.57 is: 305.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.39 : 534.56 = 221.57 : x
  2. Step 2: Convert to fraction form
    387.39/534.56 = 221.57/x
  3. Step 3: Cross multiply
    387.39x = 534.56 × 221.57
  4. Step 4: Simplify right side
    387.39x = 118,442.46
  5. Step 5: Solve for x
    x = 118,442.46/387.39
  6. Step 6: Final answer
    x = 305.74

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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.