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Finding the Fourth Proportional to 8,139.80, 12,209.70 and 7,686.20

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Solution

The fourth proportional to 8,139.80, 12,209.70 and 7,686.20 is: 11,529.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    8,139.80 : 12,209.70 = 7,686.20 : x
  2. Step 2: Convert to fraction form
    8,139.80/12,209.70 = 7,686.20/x
  3. Step 3: Cross multiply
    8,139.80x = 12,209.70 × 7,686.20
  4. Step 4: Simplify right side
    8,139.80x = 93,846,196.14
  5. Step 5: Solve for x
    x = 93,846,196.14/8,139.80
  6. Step 6: Final answer
    x = 11,529.30

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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.