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Finding the Fourth Proportional to 85.84, 128.49 and 70.66

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Solution

The fourth proportional to 85.84, 128.49 and 70.66 is: 105.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.84 : 128.49 = 70.66 : x
  2. Step 2: Convert to fraction form
    85.84/128.49 = 70.66/x
  3. Step 3: Cross multiply
    85.84x = 128.49 × 70.66
  4. Step 4: Simplify right side
    85.84x = 9,079.10
  5. Step 5: Solve for x
    x = 9,079.10/85.84
  6. Step 6: Final answer
    x = 105.77

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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.