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Finding the Fourth Proportional to 129.21, 193.61 and 98.70

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Solution

The fourth proportional to 129.21, 193.61 and 98.70 is: 147.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.21 : 193.61 = 98.70 : x
  2. Step 2: Convert to fraction form
    129.21/193.61 = 98.70/x
  3. Step 3: Cross multiply
    129.21x = 193.61 × 98.70
  4. Step 4: Simplify right side
    129.21x = 19,108.81
  5. Step 5: Solve for x
    x = 19,108.81/129.21
  6. Step 6: Final answer
    x = 147.89

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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.