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Finding the Fourth Proportional to 143.34, 215.40 and 85.57

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Solution

The fourth proportional to 143.34, 215.40 and 85.57 is: 128.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.34 : 215.40 = 85.57 : x
  2. Step 2: Convert to fraction form
    143.34/215.40 = 85.57/x
  3. Step 3: Cross multiply
    143.34x = 215.40 × 85.57
  4. Step 4: Simplify right side
    143.34x = 18,430.70
  5. Step 5: Solve for x
    x = 18,430.70/143.34
  6. Step 6: Final answer
    x = 128.58

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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.