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Finding the Fourth Proportional to 139.64, 209.40 and 75.50

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Solution

The fourth proportional to 139.64, 209.40 and 75.50 is: 113.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.64 : 209.40 = 75.50 : x
  2. Step 2: Convert to fraction form
    139.64/209.40 = 75.50/x
  3. Step 3: Cross multiply
    139.64x = 209.40 × 75.50
  4. Step 4: Simplify right side
    139.64x = 15,809.70
  5. Step 5: Solve for x
    x = 15,809.70/139.64
  6. Step 6: Final answer
    x = 113.22

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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.