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Finding the Fourth Proportional to 141.20, 210.64 and 128.96

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Solution

The fourth proportional to 141.20, 210.64 and 128.96 is: 192.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    141.20 : 210.64 = 128.96 : x
  2. Step 2: Convert to fraction form
    141.20/210.64 = 128.96/x
  3. Step 3: Cross multiply
    141.20x = 210.64 × 128.96
  4. Step 4: Simplify right side
    141.20x = 27,164.13
  5. Step 5: Solve for x
    x = 27,164.13/141.20
  6. Step 6: Final answer
    x = 192.38

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.