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Finding the Fourth Proportional to 742.64, 1,107.44 and 640.64

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Solution

The fourth proportional to 742.64, 1,107.44 and 640.64 is: 955.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    742.64 : 1,107.44 = 640.64 : x
  2. Step 2: Convert to fraction form
    742.64/1,107.44 = 640.64/x
  3. Step 3: Cross multiply
    742.64x = 1,107.44 × 640.64
  4. Step 4: Simplify right side
    742.64x = 709,470.36
  5. Step 5: Solve for x
    x = 709,470.36/742.64
  6. Step 6: Final answer
    x = 955.34

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.