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Finding the Fourth Proportional to 1,530, 2,111.40 and 831.39

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Solution

The fourth proportional to 1,530, 2,111.40 and 831.39 is: 1,147.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,530 : 2,111.40 = 831.39 : x
  2. Step 2: Convert to fraction form
    1,530/2,111.40 = 831.39/x
  3. Step 3: Cross multiply
    1,530x = 2,111.40 × 831.39
  4. Step 4: Simplify right side
    1,530x = 1,755,396.85
  5. Step 5: Solve for x
    x = 1,755,396.85/1,530
  6. Step 6: Final answer
    x = 1,147.32

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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.