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Finding the Fourth Proportional to 88.39, 121.85 and 85.70

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Solution

The fourth proportional to 88.39, 121.85 and 85.70 is: 118.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    88.39 : 121.85 = 85.70 : x
  2. Step 2: Convert to fraction form
    88.39/121.85 = 85.70/x
  3. Step 3: Cross multiply
    88.39x = 121.85 × 85.70
  4. Step 4: Simplify right side
    88.39x = 10,441.51
  5. Step 5: Solve for x
    x = 10,441.51/88.39
  6. Step 6: Final answer
    x = 118.14

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.