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Finding the Fourth Proportional to 869.90, 1,200.30 and 515.66

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Solution

The fourth proportional to 869.90, 1,200.30 and 515.66 is: 711.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.90 : 1,200.30 = 515.66 : x
  2. Step 2: Convert to fraction form
    869.90/1,200.30 = 515.66/x
  3. Step 3: Cross multiply
    869.90x = 1,200.30 × 515.66
  4. Step 4: Simplify right side
    869.90x = 618,946.70
  5. Step 5: Solve for x
    x = 618,946.70/869.90
  6. Step 6: Final answer
    x = 711.51

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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.