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Finding the Fourth Proportional to 869.39, 1,199.81 and 515.60

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Solution

The fourth proportional to 869.39, 1,199.81 and 515.60 is: 711.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.39 : 1,199.81 = 515.60 : x
  2. Step 2: Convert to fraction form
    869.39/1,199.81 = 515.60/x
  3. Step 3: Cross multiply
    869.39x = 1,199.81 × 515.60
  4. Step 4: Simplify right side
    869.39x = 618,622.04
  5. Step 5: Solve for x
    x = 618,622.04/869.39
  6. Step 6: Final answer
    x = 711.56

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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.