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Finding the Fourth Proportional to 823.91, 1,139.19 and 720.17

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Solution

The fourth proportional to 823.91, 1,139.19 and 720.17 is: 995.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    823.91 : 1,139.19 = 720.17 : x
  2. Step 2: Convert to fraction form
    823.91/1,139.19 = 720.17/x
  3. Step 3: Cross multiply
    823.91x = 1,139.19 × 720.17
  4. Step 4: Simplify right side
    823.91x = 820,410.46
  5. Step 5: Solve for x
    x = 820,410.46/823.91
  6. Step 6: Final answer
    x = 995.75

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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.