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Finding the Fourth Proportional to 129.60, 194.80 and 128.16

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Solution

The fourth proportional to 129.60, 194.80 and 128.16 is: 192.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.60 : 194.80 = 128.16 : x
  2. Step 2: Convert to fraction form
    129.60/194.80 = 128.16/x
  3. Step 3: Cross multiply
    129.60x = 194.80 × 128.16
  4. Step 4: Simplify right side
    129.60x = 24,965.57
  5. Step 5: Solve for x
    x = 24,965.57/129.60
  6. Step 6: Final answer
    x = 192.64

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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.