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Finding the Fourth Proportional to 811.60, 1,120.20 and 517.20

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Solution

The fourth proportional to 811.60, 1,120.20 and 517.20 is: 713.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.60 : 1,120.20 = 517.20 : x
  2. Step 2: Convert to fraction form
    811.60/1,120.20 = 517.20/x
  3. Step 3: Cross multiply
    811.60x = 1,120.20 × 517.20
  4. Step 4: Simplify right side
    811.60x = 579,367.44
  5. Step 5: Solve for x
    x = 579,367.44/811.60
  6. Step 6: Final answer
    x = 713.86

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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.