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Finding the Fourth Proportional to 111.06, 153.05 and 78.21

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Solution

The fourth proportional to 111.06, 153.05 and 78.21 is: 107.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.06 : 153.05 = 78.21 : x
  2. Step 2: Convert to fraction form
    111.06/153.05 = 78.21/x
  3. Step 3: Cross multiply
    111.06x = 153.05 × 78.21
  4. Step 4: Simplify right side
    111.06x = 11,969.65
  5. Step 5: Solve for x
    x = 11,969.65/111.06
  6. Step 6: Final answer
    x = 107.78

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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.