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Finding the Fourth Proportional to 911.28, 1,257.16 and 561.76

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Solution

The fourth proportional to 911.28, 1,257.16 and 561.76 is: 774.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.28 : 1,257.16 = 561.76 : x
  2. Step 2: Convert to fraction form
    911.28/1,257.16 = 561.76/x
  3. Step 3: Cross multiply
    911.28x = 1,257.16 × 561.76
  4. Step 4: Simplify right side
    911.28x = 706,222.20
  5. Step 5: Solve for x
    x = 706,222.20/911.28
  6. Step 6: Final answer
    x = 774.98

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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.