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Finding the Fourth Proportional to 76.64, 105.75 and 47.15

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Solution

The fourth proportional to 76.64, 105.75 and 47.15 is: 65.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.64 : 105.75 = 47.15 : x
  2. Step 2: Convert to fraction form
    76.64/105.75 = 47.15/x
  3. Step 3: Cross multiply
    76.64x = 105.75 × 47.15
  4. Step 4: Simplify right side
    76.64x = 4,985.58
  5. Step 5: Solve for x
    x = 4,985.58/76.64
  6. Step 6: Final answer
    x = 65.06

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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.