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Finding the Fourth Proportional to 162.72, 243.90 and 81.51

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Solution

The fourth proportional to 162.72, 243.90 and 81.51 is: 122.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    162.72 : 243.90 = 81.51 : x
  2. Step 2: Convert to fraction form
    162.72/243.90 = 81.51/x
  3. Step 3: Cross multiply
    162.72x = 243.90 × 81.51
  4. Step 4: Simplify right side
    162.72x = 19,880.29
  5. Step 5: Solve for x
    x = 19,880.29/162.72
  6. Step 6: Final answer
    x = 122.17

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.