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Finding the Fourth Proportional to 282.81, 390.38 and 217.20

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Solution

The fourth proportional to 282.81, 390.38 and 217.20 is: 299.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    282.81 : 390.38 = 217.20 : x
  2. Step 2: Convert to fraction form
    282.81/390.38 = 217.20/x
  3. Step 3: Cross multiply
    282.81x = 390.38 × 217.20
  4. Step 4: Simplify right side
    282.81x = 84,790.54
  5. Step 5: Solve for x
    x = 84,790.54/282.81
  6. Step 6: Final answer
    x = 299.81

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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.