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Finding the Fourth Proportional to 386.30, 579.90 and 221.90

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Solution

The fourth proportional to 386.30, 579.90 and 221.90 is: 333.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.30 : 579.90 = 221.90 : x
  2. Step 2: Convert to fraction form
    386.30/579.90 = 221.90/x
  3. Step 3: Cross multiply
    386.30x = 579.90 × 221.90
  4. Step 4: Simplify right side
    386.30x = 128,679.81
  5. Step 5: Solve for x
    x = 128,679.81/386.30
  6. Step 6: Final answer
    x = 333.11

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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.