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Finding the Fourth Proportional to 78.71, 108.51 and 74.25

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Solution

The fourth proportional to 78.71, 108.51 and 74.25 is: 102.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.71 : 108.51 = 74.25 : x
  2. Step 2: Convert to fraction form
    78.71/108.51 = 74.25/x
  3. Step 3: Cross multiply
    78.71x = 108.51 × 74.25
  4. Step 4: Simplify right side
    78.71x = 8,056.87
  5. Step 5: Solve for x
    x = 8,056.87/78.71
  6. Step 6: Final answer
    x = 102.36

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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.