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Finding the Fourth Proportional to 2,139.72, 3,208.96 and 840.88

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Solution

The fourth proportional to 2,139.72, 3,208.96 and 840.88 is: 1,261.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,139.72 : 3,208.96 = 840.88 : x
  2. Step 2: Convert to fraction form
    2,139.72/3,208.96 = 840.88/x
  3. Step 3: Cross multiply
    2,139.72x = 3,208.96 × 840.88
  4. Step 4: Simplify right side
    2,139.72x = 2,698,350.28
  5. Step 5: Solve for x
    x = 2,698,350.28/2,139.72
  6. Step 6: Final answer
    x = 1,261.08

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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.