Home / 20,981.40-31,399.20-19,231.80

Finding the Fourth Proportional to 20,981.40, 31,399.20 and 19,231.80

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Solution

The fourth proportional to 20,981.40, 31,399.20 and 19,231.80 is: 28,780.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    20,981.40 : 31,399.20 = 19,231.80 : x
  2. Step 2: Convert to fraction form
    20,981.40/31,399.20 = 19,231.80/x
  3. Step 3: Cross multiply
    20,981.40x = 31,399.20 × 19,231.80
  4. Step 4: Simplify right side
    20,981.40x = 603,863,134.56
  5. Step 5: Solve for x
    x = 603,863,134.56/20,981.40
  6. Step 6: Final answer
    x = 28,780.88

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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.