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Finding the Fourth Proportional to 911.72, 1,256.90 and 771.28

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Solution

The fourth proportional to 911.72, 1,256.90 and 771.28 is: 1,063.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.72 : 1,256.90 = 771.28 : x
  2. Step 2: Convert to fraction form
    911.72/1,256.90 = 771.28/x
  3. Step 3: Cross multiply
    911.72x = 1,256.90 × 771.28
  4. Step 4: Simplify right side
    911.72x = 969,421.83
  5. Step 5: Solve for x
    x = 969,421.83/911.72
  6. Step 6: Final answer
    x = 1,063.29

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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.