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Finding the Fourth Proportional to 318.28, 438.90 and 281.80

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Solution

The fourth proportional to 318.28, 438.90 and 281.80 is: 388.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.28 : 438.90 = 281.80 : x
  2. Step 2: Convert to fraction form
    318.28/438.90 = 281.80/x
  3. Step 3: Cross multiply
    318.28x = 438.90 × 281.80
  4. Step 4: Simplify right side
    318.28x = 123,682.02
  5. Step 5: Solve for x
    x = 123,682.02/318.28
  6. Step 6: Final answer
    x = 388.60

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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.