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Finding the Fourth Proportional to 782.55, 1,079.61 and 720.39

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Solution

The fourth proportional to 782.55, 1,079.61 and 720.39 is: 993.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.55 : 1,079.61 = 720.39 : x
  2. Step 2: Convert to fraction form
    782.55/1,079.61 = 720.39/x
  3. Step 3: Cross multiply
    782.55x = 1,079.61 × 720.39
  4. Step 4: Simplify right side
    782.55x = 777,740.25
  5. Step 5: Solve for x
    x = 777,740.25/782.55
  6. Step 6: Final answer
    x = 993.85

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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.