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Finding the Fourth Proportional to 218.95, 328.39 and 81.95

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Solution

The fourth proportional to 218.95, 328.39 and 81.95 is: 122.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.95 : 328.39 = 81.95 : x
  2. Step 2: Convert to fraction form
    218.95/328.39 = 81.95/x
  3. Step 3: Cross multiply
    218.95x = 328.39 × 81.95
  4. Step 4: Simplify right side
    218.95x = 26,911.56
  5. Step 5: Solve for x
    x = 26,911.56/218.95
  6. Step 6: Final answer
    x = 122.91

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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.