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Finding the Fourth Proportional to 2,080, 3,120 and 1,259.20

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Solution

The fourth proportional to 2,080, 3,120 and 1,259.20 is: 1,888.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,080 : 3,120 = 1,259.20 : x
  2. Step 2: Convert to fraction form
    2,080/3,120 = 1,259.20/x
  3. Step 3: Cross multiply
    2,080x = 3,120 × 1,259.20
  4. Step 4: Simplify right side
    2,080x = 3,928,704
  5. Step 5: Solve for x
    x = 3,928,704/2,080
  6. Step 6: Final answer
    x = 1,888.80

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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.