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Finding the Fourth Proportional to 139.56, 210.15 and 103.74

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Solution

The fourth proportional to 139.56, 210.15 and 103.74 is: 156.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.56 : 210.15 = 103.74 : x
  2. Step 2: Convert to fraction form
    139.56/210.15 = 103.74/x
  3. Step 3: Cross multiply
    139.56x = 210.15 × 103.74
  4. Step 4: Simplify right side
    139.56x = 21,800.96
  5. Step 5: Solve for x
    x = 21,800.96/139.56
  6. Step 6: Final answer
    x = 156.21

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.