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Finding the Fourth Proportional to 86.22, 128.76 and 84.06

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Solution

The fourth proportional to 86.22, 128.76 and 84.06 is: 125.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.22 : 128.76 = 84.06 : x
  2. Step 2: Convert to fraction form
    86.22/128.76 = 84.06/x
  3. Step 3: Cross multiply
    86.22x = 128.76 × 84.06
  4. Step 4: Simplify right side
    86.22x = 10,823.57
  5. Step 5: Solve for x
    x = 10,823.57/86.22
  6. Step 6: Final answer
    x = 125.53

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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.