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Finding the Fourth Proportional to 85.15, 127.77 and 31.08

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Solution

The fourth proportional to 85.15, 127.77 and 31.08 is: 46.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.15 : 127.77 = 31.08 : x
  2. Step 2: Convert to fraction form
    85.15/127.77 = 31.08/x
  3. Step 3: Cross multiply
    85.15x = 127.77 × 31.08
  4. Step 4: Simplify right side
    85.15x = 3,971.21
  5. Step 5: Solve for x
    x = 3,971.21/85.15
  6. Step 6: Final answer
    x = 46.64

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.