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Finding the Fourth Proportional to 1,209.06, 1,812.96 and 428.76

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Solution

The fourth proportional to 1,209.06, 1,812.96 and 428.76 is: 642.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.06 : 1,812.96 = 428.76 : x
  2. Step 2: Convert to fraction form
    1,209.06/1,812.96 = 428.76/x
  3. Step 3: Cross multiply
    1,209.06x = 1,812.96 × 428.76
  4. Step 4: Simplify right side
    1,209.06x = 777,324.73
  5. Step 5: Solve for x
    x = 777,324.73/1,209.06
  6. Step 6: Final answer
    x = 642.92

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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.