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Finding the Fourth Proportional to 155.89, 215.22 and 121

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Solution

The fourth proportional to 155.89, 215.22 and 121 is: 167.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    155.89 : 215.22 = 121 : x
  2. Step 2: Convert to fraction form
    155.89/215.22 = 121/x
  3. Step 3: Cross multiply
    155.89x = 215.22 × 121
  4. Step 4: Simplify right side
    155.89x = 26,041.62
  5. Step 5: Solve for x
    x = 26,041.62/155.89
  6. Step 6: Final answer
    x = 167.05

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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.