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Finding the Fourth Proportional to 821.86, 1,231.57 and 761.11

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Solution

The fourth proportional to 821.86, 1,231.57 and 761.11 is: 1,140.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.86 : 1,231.57 = 761.11 : x
  2. Step 2: Convert to fraction form
    821.86/1,231.57 = 761.11/x
  3. Step 3: Cross multiply
    821.86x = 1,231.57 × 761.11
  4. Step 4: Simplify right side
    821.86x = 937,358.12
  5. Step 5: Solve for x
    x = 937,358.12/821.86
  6. Step 6: Final answer
    x = 1,140.54

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.