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Finding the Fourth Proportional to 310.99, 428.72 and 217.45

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Solution

The fourth proportional to 310.99, 428.72 and 217.45 is: 299.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.99 : 428.72 = 217.45 : x
  2. Step 2: Convert to fraction form
    310.99/428.72 = 217.45/x
  3. Step 3: Cross multiply
    310.99x = 428.72 × 217.45
  4. Step 4: Simplify right side
    310.99x = 93,223.41
  5. Step 5: Solve for x
    x = 93,223.41/310.99
  6. Step 6: Final answer
    x = 299.76

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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.