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Finding the Fourth Proportional to 117.52, 161.90 and 78.64

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Solution

The fourth proportional to 117.52, 161.90 and 78.64 is: 108.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    117.52 : 161.90 = 78.64 : x
  2. Step 2: Convert to fraction form
    117.52/161.90 = 78.64/x
  3. Step 3: Cross multiply
    117.52x = 161.90 × 78.64
  4. Step 4: Simplify right side
    117.52x = 12,731.82
  5. Step 5: Solve for x
    x = 12,731.82/117.52
  6. Step 6: Final answer
    x = 108.34

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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.