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Finding the Fourth Proportional to 121.81, 181.41 and 115.60

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Solution

The fourth proportional to 121.81, 181.41 and 115.60 is: 172.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.81 : 181.41 = 115.60 : x
  2. Step 2: Convert to fraction form
    121.81/181.41 = 115.60/x
  3. Step 3: Cross multiply
    121.81x = 181.41 × 115.60
  4. Step 4: Simplify right side
    121.81x = 20,971.00
  5. Step 5: Solve for x
    x = 20,971.00/121.81
  6. Step 6: Final answer
    x = 172.16

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.