Home / 1,128.20-1,690.68-839.30

Finding the Fourth Proportional to 1,128.20, 1,690.68 and 839.30

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Solution

The fourth proportional to 1,128.20, 1,690.68 and 839.30 is: 1,257.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.20 : 1,690.68 = 839.30 : x
  2. Step 2: Convert to fraction form
    1,128.20/1,690.68 = 839.30/x
  3. Step 3: Cross multiply
    1,128.20x = 1,690.68 × 839.30
  4. Step 4: Simplify right side
    1,128.20x = 1,418,987.72
  5. Step 5: Solve for x
    x = 1,418,987.72/1,128.20
  6. Step 6: Final answer
    x = 1,257.74

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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.