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Finding the Fourth Proportional to 387.18, 534.40 and 221.47

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Solution

The fourth proportional to 387.18, 534.40 and 221.47 is: 305.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.18 : 534.40 = 221.47 : x
  2. Step 2: Convert to fraction form
    387.18/534.40 = 221.47/x
  3. Step 3: Cross multiply
    387.18x = 534.40 × 221.47
  4. Step 4: Simplify right side
    387.18x = 118,351.68
  5. Step 5: Solve for x
    x = 118,351.68/387.18
  6. Step 6: Final answer
    x = 305.68

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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.