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Finding the Fourth Proportional to 385.80, 579.06 and 212.55

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Solution

The fourth proportional to 385.80, 579.06 and 212.55 is: 319.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.80 : 579.06 = 212.55 : x
  2. Step 2: Convert to fraction form
    385.80/579.06 = 212.55/x
  3. Step 3: Cross multiply
    385.80x = 579.06 × 212.55
  4. Step 4: Simplify right side
    385.80x = 123,079.20
  5. Step 5: Solve for x
    x = 123,079.20/385.80
  6. Step 6: Final answer
    x = 319.02

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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.