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Finding the Fourth Proportional to 172.89, 238.58 and 99.21

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Solution

The fourth proportional to 172.89, 238.58 and 99.21 is: 136.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.89 : 238.58 = 99.21 : x
  2. Step 2: Convert to fraction form
    172.89/238.58 = 99.21/x
  3. Step 3: Cross multiply
    172.89x = 238.58 × 99.21
  4. Step 4: Simplify right side
    172.89x = 23,669.03
  5. Step 5: Solve for x
    x = 23,669.03/172.89
  6. Step 6: Final answer
    x = 136.90

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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.