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Finding the Fourth Proportional to 879.70, 1,318.20 and 831.10

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Solution

The fourth proportional to 879.70, 1,318.20 and 831.10 is: 1,245.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.70 : 1,318.20 = 831.10 : x
  2. Step 2: Convert to fraction form
    879.70/1,318.20 = 831.10/x
  3. Step 3: Cross multiply
    879.70x = 1,318.20 × 831.10
  4. Step 4: Simplify right side
    879.70x = 1,095,556.02
  5. Step 5: Solve for x
    x = 1,095,556.02/879.70
  6. Step 6: Final answer
    x = 1,245.37

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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.