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Finding the Fourth Proportional to 13,321.20, 19,981.80 and 7,780.80

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Solution

The fourth proportional to 13,321.20, 19,981.80 and 7,780.80 is: 11,671.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    13,321.20 : 19,981.80 = 7,780.80 : x
  2. Step 2: Convert to fraction form
    13,321.20/19,981.80 = 7,780.80/x
  3. Step 3: Cross multiply
    13,321.20x = 19,981.80 × 7,780.80
  4. Step 4: Simplify right side
    13,321.20x = 155,474,389.44
  5. Step 5: Solve for x
    x = 155,474,389.44/13,321.20
  6. Step 6: Final answer
    x = 11,671.20

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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.