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Finding the Fourth Proportional to 310.87, 428.98 and 212.66

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Solution

The fourth proportional to 310.87, 428.98 and 212.66 is: 293.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.87 : 428.98 = 212.66 : x
  2. Step 2: Convert to fraction form
    310.87/428.98 = 212.66/x
  3. Step 3: Cross multiply
    310.87x = 428.98 × 212.66
  4. Step 4: Simplify right side
    310.87x = 91,223.68
  5. Step 5: Solve for x
    x = 91,223.68/310.87
  6. Step 6: Final answer
    x = 293.45

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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.