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Finding the Fourth Proportional to 20,129.60, 30,190.80 and 12,720.80

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Solution

The fourth proportional to 20,129.60, 30,190.80 and 12,720.80 is: 19,078.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    20,129.60 : 30,190.80 = 12,720.80 : x
  2. Step 2: Convert to fraction form
    20,129.60/30,190.80 = 12,720.80/x
  3. Step 3: Cross multiply
    20,129.60x = 30,190.80 × 12,720.80
  4. Step 4: Simplify right side
    20,129.60x = 384,051,128.64
  5. Step 5: Solve for x
    x = 384,051,128.64/20,129.60
  6. Step 6: Final answer
    x = 19,078.92

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1.5x scale

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.