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Finding the Fourth Proportional to 310.39, 428.19 and 199.81

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Solution

The fourth proportional to 310.39, 428.19 and 199.81 is: 275.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.39 : 428.19 = 199.81 : x
  2. Step 2: Convert to fraction form
    310.39/428.19 = 199.81/x
  3. Step 3: Cross multiply
    310.39x = 428.19 × 199.81
  4. Step 4: Simplify right side
    310.39x = 85,556.64
  5. Step 5: Solve for x
    x = 85,556.64/310.39
  6. Step 6: Final answer
    x = 275.64

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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.