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Finding the Fourth Proportional to 749.64, 1,121.22 and 642.72

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Solution

The fourth proportional to 749.64, 1,121.22 and 642.72 is: 961.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    749.64 : 1,121.22 = 642.72 : x
  2. Step 2: Convert to fraction form
    749.64/1,121.22 = 642.72/x
  3. Step 3: Cross multiply
    749.64x = 1,121.22 × 642.72
  4. Step 4: Simplify right side
    749.64x = 720,630.52
  5. Step 5: Solve for x
    x = 720,630.52/749.64
  6. Step 6: Final answer
    x = 961.30

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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.