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Finding the Fourth Proportional to 821.08, 1,231.66 and 787.16

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Solution

The fourth proportional to 821.08, 1,231.66 and 787.16 is: 1,180.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.08 : 1,231.66 = 787.16 : x
  2. Step 2: Convert to fraction form
    821.08/1,231.66 = 787.16/x
  3. Step 3: Cross multiply
    821.08x = 1,231.66 × 787.16
  4. Step 4: Simplify right side
    821.08x = 969,513.49
  5. Step 5: Solve for x
    x = 969,513.49/821.08
  6. Step 6: Final answer
    x = 1,180.78

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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.