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Finding the Fourth Proportional to 215.75, 323.64 and 78.86

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Solution

The fourth proportional to 215.75, 323.64 and 78.86 is: 118.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.75 : 323.64 = 78.86 : x
  2. Step 2: Convert to fraction form
    215.75/323.64 = 78.86/x
  3. Step 3: Cross multiply
    215.75x = 323.64 × 78.86
  4. Step 4: Simplify right side
    215.75x = 25,522.25
  5. Step 5: Solve for x
    x = 25,522.25/215.75
  6. Step 6: Final answer
    x = 118.30

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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.