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Finding the Fourth Proportional to 1,939.62, 2,909.40 and 478.79

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Solution

The fourth proportional to 1,939.62, 2,909.40 and 478.79 is: 718.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,939.62 : 2,909.40 = 478.79 : x
  2. Step 2: Convert to fraction form
    1,939.62/2,909.40 = 478.79/x
  3. Step 3: Cross multiply
    1,939.62x = 2,909.40 × 478.79
  4. Step 4: Simplify right side
    1,939.62x = 1,392,986.19
  5. Step 5: Solve for x
    x = 1,392,986.19/1,939.62
  6. Step 6: Final answer
    x = 718.17

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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.