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Finding the Fourth Proportional to 219.21, 328.78 and 137.85

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Solution

The fourth proportional to 219.21, 328.78 and 137.85 is: 206.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    219.21 : 328.78 = 137.85 : x
  2. Step 2: Convert to fraction form
    219.21/328.78 = 137.85/x
  3. Step 3: Cross multiply
    219.21x = 328.78 × 137.85
  4. Step 4: Simplify right side
    219.21x = 45,322.32
  5. Step 5: Solve for x
    x = 45,322.32/219.21
  6. Step 6: Final answer
    x = 206.75

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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.