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Finding the Fourth Proportional to 85.15, 117.45 and 61.81

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Solution

The fourth proportional to 85.15, 117.45 and 61.81 is: 85.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.15 : 117.45 = 61.81 : x
  2. Step 2: Convert to fraction form
    85.15/117.45 = 61.81/x
  3. Step 3: Cross multiply
    85.15x = 117.45 × 61.81
  4. Step 4: Simplify right side
    85.15x = 7,259.95
  5. Step 5: Solve for x
    x = 7,259.95/85.15
  6. Step 6: Final answer
    x = 85.26

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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.