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Finding the Fourth Proportional to 157.96, 217.90 and 99.72

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Solution

The fourth proportional to 157.96, 217.90 and 99.72 is: 137.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    157.96 : 217.90 = 99.72 : x
  2. Step 2: Convert to fraction form
    157.96/217.90 = 99.72/x
  3. Step 3: Cross multiply
    157.96x = 217.90 × 99.72
  4. Step 4: Simplify right side
    157.96x = 21,728.99
  5. Step 5: Solve for x
    x = 21,728.99/157.96
  6. Step 6: Final answer
    x = 137.56

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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.