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Finding the Fourth Proportional to 123.20, 172.80 and 123.20

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Solution

The fourth proportional to 123.20, 172.80 and 123.20 is: 172.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.20 : 172.80 = 123.20 : x
  2. Step 2: Convert to fraction form
    123.20/172.80 = 123.20/x
  3. Step 3: Cross multiply
    123.20x = 172.80 × 123.20
  4. Step 4: Simplify right side
    123.20x = 21,288.96
  5. Step 5: Solve for x
    x = 21,288.96/123.20
  6. Step 6: Final answer
    x = 172.80

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Why These Related Problems?

These problems maintain the same ratio (1.40) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.