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Finding the Fourth Proportional to 86.07, 128.88 and 70.92

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Solution

The fourth proportional to 86.07, 128.88 and 70.92 is: 106.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.07 : 128.88 = 70.92 : x
  2. Step 2: Convert to fraction form
    86.07/128.88 = 70.92/x
  3. Step 3: Cross multiply
    86.07x = 128.88 × 70.92
  4. Step 4: Simplify right side
    86.07x = 9,139.90
  5. Step 5: Solve for x
    x = 9,139.90/86.07
  6. Step 6: Final answer
    x = 106.19

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.