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Finding the Fourth Proportional to 218.80, 328.28 and 90.64

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Solution

The fourth proportional to 218.80, 328.28 and 90.64 is: 135.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.80 : 328.28 = 90.64 : x
  2. Step 2: Convert to fraction form
    218.80/328.28 = 90.64/x
  3. Step 3: Cross multiply
    218.80x = 328.28 × 90.64
  4. Step 4: Simplify right side
    218.80x = 29,755.30
  5. Step 5: Solve for x
    x = 29,755.30/218.80
  6. Step 6: Final answer
    x = 135.99

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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.