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Finding the Fourth Proportional to 913.78, 1,261.02 and 520.80

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Solution

The fourth proportional to 913.78, 1,261.02 and 520.80 is: 718.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    913.78 : 1,261.02 = 520.80 : x
  2. Step 2: Convert to fraction form
    913.78/1,261.02 = 520.80/x
  3. Step 3: Cross multiply
    913.78x = 1,261.02 × 520.80
  4. Step 4: Simplify right side
    913.78x = 656,744.15
  5. Step 5: Solve for x
    x = 656,744.15/913.78
  6. Step 6: Final answer
    x = 718.71

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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.