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Finding the Fourth Proportional to 913.86, 1,261.19 and 520.90

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Solution

The fourth proportional to 913.86, 1,261.19 and 520.90 is: 718.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    913.86 : 1,261.19 = 520.90 : x
  2. Step 2: Convert to fraction form
    913.86/1,261.19 = 520.90/x
  3. Step 3: Cross multiply
    913.86x = 1,261.19 × 520.90
  4. Step 4: Simplify right side
    913.86x = 656,952.02
  5. Step 5: Solve for x
    x = 656,952.02/913.86
  6. Step 6: Final answer
    x = 718.88

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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.