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Finding the Fourth Proportional to 128.39, 177.18 and 70.17

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Solution

The fourth proportional to 128.39, 177.18 and 70.17 is: 96.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.39 : 177.18 = 70.17 : x
  2. Step 2: Convert to fraction form
    128.39/177.18 = 70.17/x
  3. Step 3: Cross multiply
    128.39x = 177.18 × 70.17
  4. Step 4: Simplify right side
    128.39x = 12,433.18
  5. Step 5: Solve for x
    x = 12,433.18/128.39
  6. Step 6: Final answer
    x = 96.84

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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.