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Finding the Fourth Proportional to 172.80, 238.08 and 138.24

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Solution

The fourth proportional to 172.80, 238.08 and 138.24 is: 190.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.80 : 238.08 = 138.24 : x
  2. Step 2: Convert to fraction form
    172.80/238.08 = 138.24/x
  3. Step 3: Cross multiply
    172.80x = 238.08 × 138.24
  4. Step 4: Simplify right side
    172.80x = 32,912.18
  5. Step 5: Solve for x
    x = 32,912.18/172.80
  6. Step 6: Final answer
    x = 190.46

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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.