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Finding the Fourth Proportional to 78.06, 107.66 and 66.48

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Solution

The fourth proportional to 78.06, 107.66 and 66.48 is: 91.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.06 : 107.66 = 66.48 : x
  2. Step 2: Convert to fraction form
    78.06/107.66 = 66.48/x
  3. Step 3: Cross multiply
    78.06x = 107.66 × 66.48
  4. Step 4: Simplify right side
    78.06x = 7,157.24
  5. Step 5: Solve for x
    x = 7,157.24/78.06
  6. Step 6: Final answer
    x = 91.69

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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.