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Finding the Fourth Proportional to 121.47, 167.58 and 77.81

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Solution

The fourth proportional to 121.47, 167.58 and 77.81 is: 107.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.47 : 167.58 = 77.81 : x
  2. Step 2: Convert to fraction form
    121.47/167.58 = 77.81/x
  3. Step 3: Cross multiply
    121.47x = 167.58 × 77.81
  4. Step 4: Simplify right side
    121.47x = 13,038.56
  5. Step 5: Solve for x
    x = 13,038.56/121.47
  6. Step 6: Final answer
    x = 107.34

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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.