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Finding the Fourth Proportional to 115.19, 172.64 and 54.20

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Solution

The fourth proportional to 115.19, 172.64 and 54.20 is: 81.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.19 : 172.64 = 54.20 : x
  2. Step 2: Convert to fraction form
    115.19/172.64 = 54.20/x
  3. Step 3: Cross multiply
    115.19x = 172.64 × 54.20
  4. Step 4: Simplify right side
    115.19x = 9,357.22
  5. Step 5: Solve for x
    x = 9,357.22/115.19
  6. Step 6: Final answer
    x = 81.23

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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.