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Finding the Fourth Proportional to 839.40, 1,158.78 and 789.54

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Solution

The fourth proportional to 839.40, 1,158.78 and 789.54 is: 1,089.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.40 : 1,158.78 = 789.54 : x
  2. Step 2: Convert to fraction form
    839.40/1,158.78 = 789.54/x
  3. Step 3: Cross multiply
    839.40x = 1,158.78 × 789.54
  4. Step 4: Simplify right side
    839.40x = 914,903.16
  5. Step 5: Solve for x
    x = 914,903.16/839.40
  6. Step 6: Final answer
    x = 1,089.95

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1.5x scale

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.