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Finding the Fourth Proportional to 85.34, 117.85 and 54.31

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Solution

The fourth proportional to 85.34, 117.85 and 54.31 is: 75.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.34 : 117.85 = 54.31 : x
  2. Step 2: Convert to fraction form
    85.34/117.85 = 54.31/x
  3. Step 3: Cross multiply
    85.34x = 117.85 × 54.31
  4. Step 4: Simplify right side
    85.34x = 6,400.43
  5. Step 5: Solve for x
    x = 6,400.43/85.34
  6. Step 6: Final answer
    x = 75.00

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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.