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Finding the Fourth Proportional to 86.24, 128.58 and 79.36

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Solution

The fourth proportional to 86.24, 128.58 and 79.36 is: 118.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.24 : 128.58 = 79.36 : x
  2. Step 2: Convert to fraction form
    86.24/128.58 = 79.36/x
  3. Step 3: Cross multiply
    86.24x = 128.58 × 79.36
  4. Step 4: Simplify right side
    86.24x = 10,204.11
  5. Step 5: Solve for x
    x = 10,204.11/86.24
  6. Step 6: Final answer
    x = 118.32

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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.