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Finding the Fourth Proportional to 157.39, 217.15 and 91

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Solution

The fourth proportional to 157.39, 217.15 and 91 is: 125.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    157.39 : 217.15 = 91 : x
  2. Step 2: Convert to fraction form
    157.39/217.15 = 91/x
  3. Step 3: Cross multiply
    157.39x = 217.15 × 91
  4. Step 4: Simplify right side
    157.39x = 19,760.65
  5. Step 5: Solve for x
    x = 19,760.65/157.39
  6. Step 6: Final answer
    x = 125.55

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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.