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Finding the Fourth Proportional to 387.09, 534.15 and 221.31

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Solution

The fourth proportional to 387.09, 534.15 and 221.31 is: 305.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.09 : 534.15 = 221.31 : x
  2. Step 2: Convert to fraction form
    387.09/534.15 = 221.31/x
  3. Step 3: Cross multiply
    387.09x = 534.15 × 221.31
  4. Step 4: Simplify right side
    387.09x = 118,212.74
  5. Step 5: Solve for x
    x = 118,212.74/387.09
  6. Step 6: Final answer
    x = 305.39

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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.