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Finding the Fourth Proportional to 172.63, 258.54 and 85.81

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Solution

The fourth proportional to 172.63, 258.54 and 85.81 is: 128.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.63 : 258.54 = 85.81 : x
  2. Step 2: Convert to fraction form
    172.63/258.54 = 85.81/x
  3. Step 3: Cross multiply
    172.63x = 258.54 × 85.81
  4. Step 4: Simplify right side
    172.63x = 22,185.32
  5. Step 5: Solve for x
    x = 22,185.32/172.63
  6. Step 6: Final answer
    x = 128.51

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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.