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Finding the Fourth Proportional to 1,390.28, 2,085.96 and 659.48

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Solution

The fourth proportional to 1,390.28, 2,085.96 and 659.48 is: 989.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.28 : 2,085.96 = 659.48 : x
  2. Step 2: Convert to fraction form
    1,390.28/2,085.96 = 659.48/x
  3. Step 3: Cross multiply
    1,390.28x = 2,085.96 × 659.48
  4. Step 4: Simplify right side
    1,390.28x = 1,375,648.90
  5. Step 5: Solve for x
    x = 1,375,648.90/1,390.28
  6. Step 6: Final answer
    x = 989.48

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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.