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Finding the Fourth Proportional to 326.80, 489.70 and 261.55

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Solution

The fourth proportional to 326.80, 489.70 and 261.55 is: 391.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    326.80 : 489.70 = 261.55 : x
  2. Step 2: Convert to fraction form
    326.80/489.70 = 261.55/x
  3. Step 3: Cross multiply
    326.80x = 489.70 × 261.55
  4. Step 4: Simplify right side
    326.80x = 128,081.04
  5. Step 5: Solve for x
    x = 128,081.04/326.80
  6. Step 6: Final answer
    x = 391.92

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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.