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Finding the Fourth Proportional to 172.72, 237.90 and 128.98

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Solution

The fourth proportional to 172.72, 237.90 and 128.98 is: 177.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.72 : 237.90 = 128.98 : x
  2. Step 2: Convert to fraction form
    172.72/237.90 = 128.98/x
  3. Step 3: Cross multiply
    172.72x = 237.90 × 128.98
  4. Step 4: Simplify right side
    172.72x = 30,684.34
  5. Step 5: Solve for x
    x = 30,684.34/172.72
  6. Step 6: Final answer
    x = 177.65

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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.