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Finding the Fourth Proportional to 218.90, 328.16 and 121.39

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Solution

The fourth proportional to 218.90, 328.16 and 121.39 is: 181.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.90 : 328.16 = 121.39 : x
  2. Step 2: Convert to fraction form
    218.90/328.16 = 121.39/x
  3. Step 3: Cross multiply
    218.90x = 328.16 × 121.39
  4. Step 4: Simplify right side
    218.90x = 39,834.83
  5. Step 5: Solve for x
    x = 39,834.83/218.90
  6. Step 6: Final answer
    x = 181.98

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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.