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Finding the Fourth Proportional to 157.90, 218.15 and 121.18

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Solution

The fourth proportional to 157.90, 218.15 and 121.18 is: 167.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    157.90 : 218.15 = 121.18 : x
  2. Step 2: Convert to fraction form
    157.90/218.15 = 121.18/x
  3. Step 3: Cross multiply
    157.90x = 218.15 × 121.18
  4. Step 4: Simplify right side
    157.90x = 26,435.42
  5. Step 5: Solve for x
    x = 26,435.42/157.90
  6. Step 6: Final answer
    x = 167.42

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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.