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Finding the Fourth Proportional to 781.79, 1,078.40 and 516.23

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Solution

The fourth proportional to 781.79, 1,078.40 and 516.23 is: 712.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.79 : 1,078.40 = 516.23 : x
  2. Step 2: Convert to fraction form
    781.79/1,078.40 = 516.23/x
  3. Step 3: Cross multiply
    781.79x = 1,078.40 × 516.23
  4. Step 4: Simplify right side
    781.79x = 556,699.85
  5. Step 5: Solve for x
    x = 556,699.85/781.79
  6. Step 6: Final answer
    x = 712.09

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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.