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Finding the Fourth Proportional to 86.36, 128.72 and 70.04

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Solution

The fourth proportional to 86.36, 128.72 and 70.04 is: 104.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.36 : 128.72 = 70.04 : x
  2. Step 2: Convert to fraction form
    86.36/128.72 = 70.04/x
  3. Step 3: Cross multiply
    86.36x = 128.72 × 70.04
  4. Step 4: Simplify right side
    86.36x = 9,015.55
  5. Step 5: Solve for x
    x = 9,015.55/86.36
  6. Step 6: Final answer
    x = 104.39

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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.