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Finding the Fourth Proportional to 111.28, 166.60 and 78.57

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Solution

The fourth proportional to 111.28, 166.60 and 78.57 is: 117.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.28 : 166.60 = 78.57 : x
  2. Step 2: Convert to fraction form
    111.28/166.60 = 78.57/x
  3. Step 3: Cross multiply
    111.28x = 166.60 × 78.57
  4. Step 4: Simplify right side
    111.28x = 13,089.76
  5. Step 5: Solve for x
    x = 13,089.76/111.28
  6. Step 6: Final answer
    x = 117.63

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.