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Finding the Fourth Proportional to 215.42, 323.16 and 85.40

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Solution

The fourth proportional to 215.42, 323.16 and 85.40 is: 128.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.42 : 323.16 = 85.40 : x
  2. Step 2: Convert to fraction form
    215.42/323.16 = 85.40/x
  3. Step 3: Cross multiply
    215.42x = 323.16 × 85.40
  4. Step 4: Simplify right side
    215.42x = 27,597.86
  5. Step 5: Solve for x
    x = 27,597.86/215.42
  6. Step 6: Final answer
    x = 128.11

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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.