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Finding the Fourth Proportional to 911.28, 1,256.94 and 561.72

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Solution

The fourth proportional to 911.28, 1,256.94 and 561.72 is: 774.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.28 : 1,256.94 = 561.72 : x
  2. Step 2: Convert to fraction form
    911.28/1,256.94 = 561.72/x
  3. Step 3: Cross multiply
    911.28x = 1,256.94 × 561.72
  4. Step 4: Simplify right side
    911.28x = 706,048.34
  5. Step 5: Solve for x
    x = 706,048.34/911.28
  6. Step 6: Final answer
    x = 774.79

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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.