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Finding the Fourth Proportional to 287.40, 396.80 and 217.56

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Solution

The fourth proportional to 287.40, 396.80 and 217.56 is: 300.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.40 : 396.80 = 217.56 : x
  2. Step 2: Convert to fraction form
    287.40/396.80 = 217.56/x
  3. Step 3: Cross multiply
    287.40x = 396.80 × 217.56
  4. Step 4: Simplify right side
    287.40x = 86,327.81
  5. Step 5: Solve for x
    x = 86,327.81/287.40
  6. Step 6: Final answer
    x = 300.38

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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.