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Finding the Fourth Proportional to 287.32, 431.15 and 122.78

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Solution

The fourth proportional to 287.32, 431.15 and 122.78 is: 184.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.32 : 431.15 = 122.78 : x
  2. Step 2: Convert to fraction form
    287.32/431.15 = 122.78/x
  3. Step 3: Cross multiply
    287.32x = 431.15 × 122.78
  4. Step 4: Simplify right side
    287.32x = 52,933.83
  5. Step 5: Solve for x
    x = 52,933.83/287.32
  6. Step 6: Final answer
    x = 184.23

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.