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Finding the Fourth Proportional to 124.88, 172.32 and 81.20

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Solution

The fourth proportional to 124.88, 172.32 and 81.20 is: 112.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    124.88 : 172.32 = 81.20 : x
  2. Step 2: Convert to fraction form
    124.88/172.32 = 81.20/x
  3. Step 3: Cross multiply
    124.88x = 172.32 × 81.20
  4. Step 4: Simplify right side
    124.88x = 13,992.38
  5. Step 5: Solve for x
    x = 13,992.38/124.88
  6. Step 6: Final answer
    x = 112.05

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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.