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Finding the Fourth Proportional to 808.50, 1,212.75 and 261.15

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Solution

The fourth proportional to 808.50, 1,212.75 and 261.15 is: 391.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    808.50 : 1,212.75 = 261.15 : x
  2. Step 2: Convert to fraction form
    808.50/1,212.75 = 261.15/x
  3. Step 3: Cross multiply
    808.50x = 1,212.75 × 261.15
  4. Step 4: Simplify right side
    808.50x = 316,709.66
  5. Step 5: Solve for x
    x = 316,709.66/808.50
  6. Step 6: Final answer
    x = 391.73

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.