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Finding the Fourth Proportional to 157.90, 217.40 and 138.48

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Solution

The fourth proportional to 157.90, 217.40 and 138.48 is: 190.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    157.90 : 217.40 = 138.48 : x
  2. Step 2: Convert to fraction form
    157.90/217.40 = 138.48/x
  3. Step 3: Cross multiply
    157.90x = 217.40 × 138.48
  4. Step 4: Simplify right side
    157.90x = 30,104.86
  5. Step 5: Solve for x
    x = 30,104.86/157.90
  6. Step 6: Final answer
    x = 190.66

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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.