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Finding the Fourth Proportional to 207.85, 287.21 and 155.61

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Solution

The fourth proportional to 207.85, 287.21 and 155.61 is: 215.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.85 : 287.21 = 155.61 : x
  2. Step 2: Convert to fraction form
    207.85/287.21 = 155.61/x
  3. Step 3: Cross multiply
    207.85x = 287.21 × 155.61
  4. Step 4: Simplify right side
    207.85x = 44,692.75
  5. Step 5: Solve for x
    x = 44,692.75/207.85
  6. Step 6: Final answer
    x = 215.02

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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.