Home / 20,390.78-28,120.86-13,213.40

Finding the Fourth Proportional to 20,390.78, 28,120.86 and 13,213.40

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Solution

The fourth proportional to 20,390.78, 28,120.86 and 13,213.40 is: 18,222.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    20,390.78 : 28,120.86 = 13,213.40 : x
  2. Step 2: Convert to fraction form
    20,390.78/28,120.86 = 13,213.40/x
  3. Step 3: Cross multiply
    20,390.78x = 28,120.86 × 13,213.40
  4. Step 4: Simplify right side
    20,390.78x = 371,572,171.52
  5. Step 5: Solve for x
    x = 371,572,171.52/20,390.78
  6. Step 6: Final answer
    x = 18,222.56

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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.