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Finding the Fourth Proportional to 1,188.71, 1,639.51 and 789.65

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Solution

The fourth proportional to 1,188.71, 1,639.51 and 789.65 is: 1,089.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,188.71 : 1,639.51 = 789.65 : x
  2. Step 2: Convert to fraction form
    1,188.71/1,639.51 = 789.65/x
  3. Step 3: Cross multiply
    1,188.71x = 1,639.51 × 789.65
  4. Step 4: Simplify right side
    1,188.71x = 1,294,635.05
  5. Step 5: Solve for x
    x = 1,294,635.05/1,188.71
  6. Step 6: Final answer
    x = 1,089.11

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.