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Finding the Fourth Proportional to 117.91, 162.81 and 78.57

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Solution

The fourth proportional to 117.91, 162.81 and 78.57 is: 108.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    117.91 : 162.81 = 78.57 : x
  2. Step 2: Convert to fraction form
    117.91/162.81 = 78.57/x
  3. Step 3: Cross multiply
    117.91x = 162.81 × 78.57
  4. Step 4: Simplify right side
    117.91x = 12,791.98
  5. Step 5: Solve for x
    x = 12,791.98/117.91
  6. Step 6: Final answer
    x = 108.49

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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.