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Finding the Fourth Proportional to 1,939.60, 2,908.80 and 640.76

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Solution

The fourth proportional to 1,939.60, 2,908.80 and 640.76 is: 960.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,939.60 : 2,908.80 = 640.76 : x
  2. Step 2: Convert to fraction form
    1,939.60/2,908.80 = 640.76/x
  3. Step 3: Cross multiply
    1,939.60x = 2,908.80 × 640.76
  4. Step 4: Simplify right side
    1,939.60x = 1,863,842.69
  5. Step 5: Solve for x
    x = 1,863,842.69/1,939.60
  6. Step 6: Final answer
    x = 960.94

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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.