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Finding the Fourth Proportional to 157.55, 217.28 and 120.78

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Solution

The fourth proportional to 157.55, 217.28 and 120.78 is: 166.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    157.55 : 217.28 = 120.78 : x
  2. Step 2: Convert to fraction form
    157.55/217.28 = 120.78/x
  3. Step 3: Cross multiply
    157.55x = 217.28 × 120.78
  4. Step 4: Simplify right side
    157.55x = 26,242.47
  5. Step 5: Solve for x
    x = 26,242.47/157.55
  6. Step 6: Final answer
    x = 166.57

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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.