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Finding the Fourth Proportional to 911.08, 1,257.34 and 689.64

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Solution

The fourth proportional to 911.08, 1,257.34 and 689.64 is: 951.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.08 : 1,257.34 = 689.64 : x
  2. Step 2: Convert to fraction form
    911.08/1,257.34 = 689.64/x
  3. Step 3: Cross multiply
    911.08x = 1,257.34 × 689.64
  4. Step 4: Simplify right side
    911.08x = 867,111.96
  5. Step 5: Solve for x
    x = 867,111.96/911.08
  6. Step 6: Final answer
    x = 951.74

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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.