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Finding the Fourth Proportional to 143.52, 215.43 and 85.80

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Solution

The fourth proportional to 143.52, 215.43 and 85.80 is: 128.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.52 : 215.43 = 85.80 : x
  2. Step 2: Convert to fraction form
    143.52/215.43 = 85.80/x
  3. Step 3: Cross multiply
    143.52x = 215.43 × 85.80
  4. Step 4: Simplify right side
    143.52x = 18,483.89
  5. Step 5: Solve for x
    x = 18,483.89/143.52
  6. Step 6: Final answer
    x = 128.79

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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.