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Finding the Fourth Proportional to 85.33, 128.45 and 77.77

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Solution

The fourth proportional to 85.33, 128.45 and 77.77 is: 117.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.33 : 128.45 = 77.77 : x
  2. Step 2: Convert to fraction form
    85.33/128.45 = 77.77/x
  3. Step 3: Cross multiply
    85.33x = 128.45 × 77.77
  4. Step 4: Simplify right side
    85.33x = 9,988.91
  5. Step 5: Solve for x
    x = 9,988.91/85.33
  6. Step 6: Final answer
    x = 117.07

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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.