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Finding the Fourth Proportional to 85.38, 117.78 and 56.28

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Solution

The fourth proportional to 85.38, 117.78 and 56.28 is: 77.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.38 : 117.78 = 56.28 : x
  2. Step 2: Convert to fraction form
    85.38/117.78 = 56.28/x
  3. Step 3: Cross multiply
    85.38x = 117.78 × 56.28
  4. Step 4: Simplify right side
    85.38x = 6,628.66
  5. Step 5: Solve for x
    x = 6,628.66/85.38
  6. Step 6: Final answer
    x = 77.64

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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.