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Finding the Fourth Proportional to 139.90, 209.44 and 103.99

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Solution

The fourth proportional to 139.90, 209.44 and 103.99 is: 155.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.90 : 209.44 = 103.99 : x
  2. Step 2: Convert to fraction form
    139.90/209.44 = 103.99/x
  3. Step 3: Cross multiply
    139.90x = 209.44 × 103.99
  4. Step 4: Simplify right side
    139.90x = 21,779.67
  5. Step 5: Solve for x
    x = 21,779.67/139.90
  6. Step 6: Final answer
    x = 155.68

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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.