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Finding the Fourth Proportional to 12,639, 18,969.78 and 6,639.96

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Solution

The fourth proportional to 12,639, 18,969.78 and 6,639.96 is: 9,965.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    12,639 : 18,969.78 = 6,639.96 : x
  2. Step 2: Convert to fraction form
    12,639/18,969.78 = 6,639.96/x
  3. Step 3: Cross multiply
    12,639x = 18,969.78 × 6,639.96
  4. Step 4: Simplify right side
    12,639x = 125,958,580.41
  5. Step 5: Solve for x
    x = 125,958,580.41/12,639
  6. Step 6: Final answer
    x = 9,965.87

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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.