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Finding the Fourth Proportional to 1,378.12, 2,065.02 and 728.68

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Solution

The fourth proportional to 1,378.12, 2,065.02 and 728.68 is: 1,091.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.12 : 2,065.02 = 728.68 : x
  2. Step 2: Convert to fraction form
    1,378.12/2,065.02 = 728.68/x
  3. Step 3: Cross multiply
    1,378.12x = 2,065.02 × 728.68
  4. Step 4: Simplify right side
    1,378.12x = 1,504,738.77
  5. Step 5: Solve for x
    x = 1,504,738.77/1,378.12
  6. Step 6: Final answer
    x = 1,091.88

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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.