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Finding the Fourth Proportional to 781.94, 1,172.66 and 261.79

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Solution

The fourth proportional to 781.94, 1,172.66 and 261.79 is: 392.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.94 : 1,172.66 = 261.79 : x
  2. Step 2: Convert to fraction form
    781.94/1,172.66 = 261.79/x
  3. Step 3: Cross multiply
    781.94x = 1,172.66 × 261.79
  4. Step 4: Simplify right side
    781.94x = 306,986.42
  5. Step 5: Solve for x
    x = 306,986.42/781.94
  6. Step 6: Final answer
    x = 392.59

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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.