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Finding the Fourth Proportional to 78.87, 108.86 and 47.80

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Solution

The fourth proportional to 78.87, 108.86 and 47.80 is: 65.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.87 : 108.86 = 47.80 : x
  2. Step 2: Convert to fraction form
    78.87/108.86 = 47.80/x
  3. Step 3: Cross multiply
    78.87x = 108.86 × 47.80
  4. Step 4: Simplify right side
    78.87x = 5,203.51
  5. Step 5: Solve for x
    x = 5,203.51/78.87
  6. Step 6: Final answer
    x = 65.98

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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.