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Finding the Fourth Proportional to 85.30, 128.43 and 70.82

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Solution

The fourth proportional to 85.30, 128.43 and 70.82 is: 106.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.30 : 128.43 = 70.82 : x
  2. Step 2: Convert to fraction form
    85.30/128.43 = 70.82/x
  3. Step 3: Cross multiply
    85.30x = 128.43 × 70.82
  4. Step 4: Simplify right side
    85.30x = 9,095.41
  5. Step 5: Solve for x
    x = 9,095.41/85.30
  6. Step 6: Final answer
    x = 106.63

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.