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Finding the Fourth Proportional to 129.99, 179.38 and 71.78

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Solution

The fourth proportional to 129.99, 179.38 and 71.78 is: 99.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.99 : 179.38 = 71.78 : x
  2. Step 2: Convert to fraction form
    129.99/179.38 = 71.78/x
  3. Step 3: Cross multiply
    129.99x = 179.38 × 71.78
  4. Step 4: Simplify right side
    129.99x = 12,874.82
  5. Step 5: Solve for x
    x = 12,874.82/129.99
  6. Step 6: Final answer
    x = 99.04

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.