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Finding the Fourth Proportional to 811.86, 1,120.89 and 724.38

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Solution

The fourth proportional to 811.86, 1,120.89 and 724.38 is: 1,000.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.86 : 1,120.89 = 724.38 : x
  2. Step 2: Convert to fraction form
    811.86/1,120.89 = 724.38/x
  3. Step 3: Cross multiply
    811.86x = 1,120.89 × 724.38
  4. Step 4: Simplify right side
    811.86x = 811,950.30
  5. Step 5: Solve for x
    x = 811,950.30/811.86
  6. Step 6: Final answer
    x = 1,000.11

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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.