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Finding the Fourth Proportional to 78.41, 108.38 and 66.13

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Solution

The fourth proportional to 78.41, 108.38 and 66.13 is: 91.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.41 : 108.38 = 66.13 : x
  2. Step 2: Convert to fraction form
    78.41/108.38 = 66.13/x
  3. Step 3: Cross multiply
    78.41x = 108.38 × 66.13
  4. Step 4: Simplify right side
    78.41x = 7,167.06
  5. Step 5: Solve for x
    x = 7,167.06/78.41
  6. Step 6: Final answer
    x = 91.40

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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.