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Finding the Fourth Proportional to 115.82, 159.90 and 72.20

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Solution

The fourth proportional to 115.82, 159.90 and 72.20 is: 99.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.82 : 159.90 = 72.20 : x
  2. Step 2: Convert to fraction form
    115.82/159.90 = 72.20/x
  3. Step 3: Cross multiply
    115.82x = 159.90 × 72.20
  4. Step 4: Simplify right side
    115.82x = 11,544.78
  5. Step 5: Solve for x
    x = 11,544.78/115.82
  6. Step 6: Final answer
    x = 99.68

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.