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Finding the Fourth Proportional to 771.64, 1,155.84 and 641.38

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Solution

The fourth proportional to 771.64, 1,155.84 and 641.38 is: 960.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.64 : 1,155.84 = 641.38 : x
  2. Step 2: Convert to fraction form
    771.64/1,155.84 = 641.38/x
  3. Step 3: Cross multiply
    771.64x = 1,155.84 × 641.38
  4. Step 4: Simplify right side
    771.64x = 741,332.66
  5. Step 5: Solve for x
    x = 741,332.66/771.64
  6. Step 6: Final answer
    x = 960.72

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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.