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Finding the Fourth Proportional to 85.08, 117.18 and 78.24

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Solution

The fourth proportional to 85.08, 117.18 and 78.24 is: 107.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.08 : 117.18 = 78.24 : x
  2. Step 2: Convert to fraction form
    85.08/117.18 = 78.24/x
  3. Step 3: Cross multiply
    85.08x = 117.18 × 78.24
  4. Step 4: Simplify right side
    85.08x = 9,168.16
  5. Step 5: Solve for x
    x = 9,168.16/85.08
  6. Step 6: Final answer
    x = 107.76

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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.