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Finding the Fourth Proportional to 139.42, 209 and 70.98

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Solution

The fourth proportional to 139.42, 209 and 70.98 is: 106.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.42 : 209 = 70.98 : x
  2. Step 2: Convert to fraction form
    139.42/209 = 70.98/x
  3. Step 3: Cross multiply
    139.42x = 209 × 70.98
  4. Step 4: Simplify right side
    139.42x = 14,834.82
  5. Step 5: Solve for x
    x = 14,834.82/139.42
  6. Step 6: Final answer
    x = 106.40

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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.