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Finding the Fourth Proportional to 139.87, 209.53 and 91.63

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Solution

The fourth proportional to 139.87, 209.53 and 91.63 is: 137.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.87 : 209.53 = 91.63 : x
  2. Step 2: Convert to fraction form
    139.87/209.53 = 91.63/x
  3. Step 3: Cross multiply
    139.87x = 209.53 × 91.63
  4. Step 4: Simplify right side
    139.87x = 19,199.23
  5. Step 5: Solve for x
    x = 19,199.23/139.87
  6. Step 6: Final answer
    x = 137.26

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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.