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Finding the Fourth Proportional to 2,119.60, 3,179.12 and 820.40

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Solution

The fourth proportional to 2,119.60, 3,179.12 and 820.40 is: 1,230.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,119.60 : 3,179.12 = 820.40 : x
  2. Step 2: Convert to fraction form
    2,119.60/3,179.12 = 820.40/x
  3. Step 3: Cross multiply
    2,119.60x = 3,179.12 × 820.40
  4. Step 4: Simplify right side
    2,119.60x = 2,608,150.05
  5. Step 5: Solve for x
    x = 2,608,150.05/2,119.60
  6. Step 6: Final answer
    x = 1,230.49

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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.