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Finding the Fourth Proportional to 310.19, 428.21 and 199.86

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Solution

The fourth proportional to 310.19, 428.21 and 199.86 is: 275.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.19 : 428.21 = 199.86 : x
  2. Step 2: Convert to fraction form
    310.19/428.21 = 199.86/x
  3. Step 3: Cross multiply
    310.19x = 428.21 × 199.86
  4. Step 4: Simplify right side
    310.19x = 85,582.05
  5. Step 5: Solve for x
    x = 85,582.05/310.19
  6. Step 6: Final answer
    x = 275.90

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.