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Finding the Fourth Proportional to 86.79, 119.78 and 47.45

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Solution

The fourth proportional to 86.79, 119.78 and 47.45 is: 65.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.79 : 119.78 = 47.45 : x
  2. Step 2: Convert to fraction form
    86.79/119.78 = 47.45/x
  3. Step 3: Cross multiply
    86.79x = 119.78 × 47.45
  4. Step 4: Simplify right side
    86.79x = 5,682.72
  5. Step 5: Solve for x
    x = 5,682.72/86.79
  6. Step 6: Final answer
    x = 65.48

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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.