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Finding the Fourth Proportional to 143.67, 198.21 and 87.65

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Solution

The fourth proportional to 143.67, 198.21 and 87.65 is: 120.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.67 : 198.21 = 87.65 : x
  2. Step 2: Convert to fraction form
    143.67/198.21 = 87.65/x
  3. Step 3: Cross multiply
    143.67x = 198.21 × 87.65
  4. Step 4: Simplify right side
    143.67x = 17,373.19
  5. Step 5: Solve for x
    x = 17,373.19/143.67
  6. Step 6: Final answer
    x = 120.92

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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.