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Finding the Fourth Proportional to 310.42, 428.12 and 221.74

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Solution

The fourth proportional to 310.42, 428.12 and 221.74 is: 305.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.42 : 428.12 = 221.74 : x
  2. Step 2: Convert to fraction form
    310.42/428.12 = 221.74/x
  3. Step 3: Cross multiply
    310.42x = 428.12 × 221.74
  4. Step 4: Simplify right side
    310.42x = 94,929.17
  5. Step 5: Solve for x
    x = 94,929.17/310.42
  6. Step 6: Final answer
    x = 305.81

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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.