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Finding the Fourth Proportional to 157.85, 217.82 and 87.90

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Solution

The fourth proportional to 157.85, 217.82 and 87.90 is: 121.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    157.85 : 217.82 = 87.90 : x
  2. Step 2: Convert to fraction form
    157.85/217.82 = 87.90/x
  3. Step 3: Cross multiply
    157.85x = 217.82 × 87.90
  4. Step 4: Simplify right side
    157.85x = 19,145.94
  5. Step 5: Solve for x
    x = 19,145.94/157.85
  6. Step 6: Final answer
    x = 121.30

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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.