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Finding the Fourth Proportional to 1,390.28, 2,085.82 and 658.85

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Solution

The fourth proportional to 1,390.28, 2,085.82 and 658.85 is: 988.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.28 : 2,085.82 = 658.85 : x
  2. Step 2: Convert to fraction form
    1,390.28/2,085.82 = 658.85/x
  3. Step 3: Cross multiply
    1,390.28x = 2,085.82 × 658.85
  4. Step 4: Simplify right side
    1,390.28x = 1,374,230.43
  5. Step 5: Solve for x
    x = 1,374,230.43/1,390.28
  6. Step 6: Final answer
    x = 988.46

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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.