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Finding the Fourth Proportional to 86.04, 128.39 and 76.96

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Solution

The fourth proportional to 86.04, 128.39 and 76.96 is: 114.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.04 : 128.39 = 76.96 : x
  2. Step 2: Convert to fraction form
    86.04/128.39 = 76.96/x
  3. Step 3: Cross multiply
    86.04x = 128.39 × 76.96
  4. Step 4: Simplify right side
    86.04x = 9,880.51
  5. Step 5: Solve for x
    x = 9,880.51/86.04
  6. Step 6: Final answer
    x = 114.84

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.