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Finding the Fourth Proportional to 121.80, 168.18 and 113.70

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Solution

The fourth proportional to 121.80, 168.18 and 113.70 is: 157.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.80 : 168.18 = 113.70 : x
  2. Step 2: Convert to fraction form
    121.80/168.18 = 113.70/x
  3. Step 3: Cross multiply
    121.80x = 168.18 × 113.70
  4. Step 4: Simplify right side
    121.80x = 19,122.07
  5. Step 5: Solve for x
    x = 19,122.07/121.80
  6. Step 6: Final answer
    x = 157.00

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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.