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Finding the Fourth Proportional to 2,139.99, 3,209.18 and 840.75

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Solution

The fourth proportional to 2,139.99, 3,209.18 and 840.75 is: 1,260.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,139.99 : 3,209.18 = 840.75 : x
  2. Step 2: Convert to fraction form
    2,139.99/3,209.18 = 840.75/x
  3. Step 3: Cross multiply
    2,139.99x = 3,209.18 × 840.75
  4. Step 4: Simplify right side
    2,139.99x = 2,698,113.88
  5. Step 5: Solve for x
    x = 2,698,113.88/2,139.99
  6. Step 6: Final answer
    x = 1,260.81

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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.