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Finding the Fourth Proportional to 387.80, 535.13 and 221.99

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Solution

The fourth proportional to 387.80, 535.13 and 221.99 is: 306.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.80 : 535.13 = 221.99 : x
  2. Step 2: Convert to fraction form
    387.80/535.13 = 221.99/x
  3. Step 3: Cross multiply
    387.80x = 535.13 × 221.99
  4. Step 4: Simplify right side
    387.80x = 118,789.72
  5. Step 5: Solve for x
    x = 118,789.72/387.80
  6. Step 6: Final answer
    x = 306.32

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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.