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Finding the Fourth Proportional to 85.95, 128.43 and 79.47

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Solution

The fourth proportional to 85.95, 128.43 and 79.47 is: 118.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.95 : 128.43 = 79.47 : x
  2. Step 2: Convert to fraction form
    85.95/128.43 = 79.47/x
  3. Step 3: Cross multiply
    85.95x = 128.43 × 79.47
  4. Step 4: Simplify right side
    85.95x = 10,206.33
  5. Step 5: Solve for x
    x = 10,206.33/85.95
  6. Step 6: Final answer
    x = 118.75

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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.