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Finding the Fourth Proportional to 1,428.72, 2,138.44 and 769.68

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Solution

The fourth proportional to 1,428.72, 2,138.44 and 769.68 is: 1,152.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.72 : 2,138.44 = 769.68 : x
  2. Step 2: Convert to fraction form
    1,428.72/2,138.44 = 769.68/x
  3. Step 3: Cross multiply
    1,428.72x = 2,138.44 × 769.68
  4. Step 4: Simplify right side
    1,428.72x = 1,645,914.50
  5. Step 5: Solve for x
    x = 1,645,914.50/1,428.72
  6. Step 6: Final answer
    x = 1,152.02

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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.