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Finding the Fourth Proportional to 831.80, 1,245.30 and 745.40

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Solution

The fourth proportional to 831.80, 1,245.30 and 745.40 is: 1,115.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.80 : 1,245.30 = 745.40 : x
  2. Step 2: Convert to fraction form
    831.80/1,245.30 = 745.40/x
  3. Step 3: Cross multiply
    831.80x = 1,245.30 × 745.40
  4. Step 4: Simplify right side
    831.80x = 928,246.62
  5. Step 5: Solve for x
    x = 928,246.62/831.80
  6. Step 6: Final answer
    x = 1,115.95

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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.