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Finding the Fourth Proportional to 158.40, 218.70 and 121.64

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Solution

The fourth proportional to 158.40, 218.70 and 121.64 is: 167.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    158.40 : 218.70 = 121.64 : x
  2. Step 2: Convert to fraction form
    158.40/218.70 = 121.64/x
  3. Step 3: Cross multiply
    158.40x = 218.70 × 121.64
  4. Step 4: Simplify right side
    158.40x = 26,601.57
  5. Step 5: Solve for x
    x = 26,601.57/158.40
  6. Step 6: Final answer
    x = 167.94

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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.