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Finding the Fourth Proportional to 771.33, 1,157.22 and 640.74

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Solution

The fourth proportional to 771.33, 1,157.22 and 640.74 is: 961.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.33 : 1,157.22 = 640.74 : x
  2. Step 2: Convert to fraction form
    771.33/1,157.22 = 640.74/x
  3. Step 3: Cross multiply
    771.33x = 1,157.22 × 640.74
  4. Step 4: Simplify right side
    771.33x = 741,477.14
  5. Step 5: Solve for x
    x = 741,477.14/771.33
  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.