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Finding the Fourth Proportional to 121.15, 166.80 and 102.70

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Solution

The fourth proportional to 121.15, 166.80 and 102.70 is: 141.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.15 : 166.80 = 102.70 : x
  2. Step 2: Convert to fraction form
    121.15/166.80 = 102.70/x
  3. Step 3: Cross multiply
    121.15x = 166.80 × 102.70
  4. Step 4: Simplify right side
    121.15x = 17,130.36
  5. Step 5: Solve for x
    x = 17,130.36/121.15
  6. Step 6: Final answer
    x = 141.40

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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.