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Finding the Fourth Proportional to 287.91, 431.72 and 133.70

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Solution

The fourth proportional to 287.91, 431.72 and 133.70 is: 200.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.91 : 431.72 = 133.70 : x
  2. Step 2: Convert to fraction form
    287.91/431.72 = 133.70/x
  3. Step 3: Cross multiply
    287.91x = 431.72 × 133.70
  4. Step 4: Simplify right side
    287.91x = 57,720.96
  5. Step 5: Solve for x
    x = 57,720.96/287.91
  6. Step 6: Final answer
    x = 200.48

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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.