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Finding the Fourth Proportional to 85.45, 117.78 and 57.79

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Solution

The fourth proportional to 85.45, 117.78 and 57.79 is: 79.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.45 : 117.78 = 57.79 : x
  2. Step 2: Convert to fraction form
    85.45/117.78 = 57.79/x
  3. Step 3: Cross multiply
    85.45x = 117.78 × 57.79
  4. Step 4: Simplify right side
    85.45x = 6,806.51
  5. Step 5: Solve for x
    x = 6,806.51/85.45
  6. Step 6: Final answer
    x = 79.65

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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.