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Finding the Fourth Proportional to 214.80, 321.92 and 77.72

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Solution

The fourth proportional to 214.80, 321.92 and 77.72 is: 116.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    214.80 : 321.92 = 77.72 : x
  2. Step 2: Convert to fraction form
    214.80/321.92 = 77.72/x
  3. Step 3: Cross multiply
    214.80x = 321.92 × 77.72
  4. Step 4: Simplify right side
    214.80x = 25,019.62
  5. Step 5: Solve for x
    x = 25,019.62/214.80
  6. Step 6: Final answer
    x = 116.48

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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.