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Finding the Fourth Proportional to 117.12, 161.52 and 78.28

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Solution

The fourth proportional to 117.12, 161.52 and 78.28 is: 107.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    117.12 : 161.52 = 78.28 : x
  2. Step 2: Convert to fraction form
    117.12/161.52 = 78.28/x
  3. Step 3: Cross multiply
    117.12x = 161.52 × 78.28
  4. Step 4: Simplify right side
    117.12x = 12,643.79
  5. Step 5: Solve for x
    x = 12,643.79/117.12
  6. Step 6: Final answer
    x = 107.96

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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.