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Finding the Fourth Proportional to 143.72, 198.42 and 128.34

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Solution

The fourth proportional to 143.72, 198.42 and 128.34 is: 177.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.72 : 198.42 = 128.34 : x
  2. Step 2: Convert to fraction form
    143.72/198.42 = 128.34/x
  3. Step 3: Cross multiply
    143.72x = 198.42 × 128.34
  4. Step 4: Simplify right side
    143.72x = 25,465.22
  5. Step 5: Solve for x
    x = 25,465.22/143.72
  6. Step 6: Final answer
    x = 177.19

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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.