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Finding the Fourth Proportional to 78.86, 118.28 and 30.75

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Solution

The fourth proportional to 78.86, 118.28 and 30.75 is: 46.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.86 : 118.28 = 30.75 : x
  2. Step 2: Convert to fraction form
    78.86/118.28 = 30.75/x
  3. Step 3: Cross multiply
    78.86x = 118.28 × 30.75
  4. Step 4: Simplify right side
    78.86x = 3,637.11
  5. Step 5: Solve for x
    x = 3,637.11/78.86
  6. Step 6: Final answer
    x = 46.12

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.