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Finding the Fourth Proportional to 387.20, 534.36 and 221.48

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Solution

The fourth proportional to 387.20, 534.36 and 221.48 is: 305.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.20 : 534.36 = 221.48 : x
  2. Step 2: Convert to fraction form
    387.20/534.36 = 221.48/x
  3. Step 3: Cross multiply
    387.20x = 534.36 × 221.48
  4. Step 4: Simplify right side
    387.20x = 118,350.05
  5. Step 5: Solve for x
    x = 118,350.05/387.20
  6. Step 6: Final answer
    x = 305.66

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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.