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Finding the Fourth Proportional to 1,392.08, 2,086.66 and 660.78

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Solution

The fourth proportional to 1,392.08, 2,086.66 and 660.78 is: 990.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,392.08 : 2,086.66 = 660.78 : x
  2. Step 2: Convert to fraction form
    1,392.08/2,086.66 = 660.78/x
  3. Step 3: Cross multiply
    1,392.08x = 2,086.66 × 660.78
  4. Step 4: Simplify right side
    1,392.08x = 1,378,823.19
  5. Step 5: Solve for x
    x = 1,378,823.19/1,392.08
  6. Step 6: Final answer
    x = 990.48

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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.