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Finding the Fourth Proportional to 85.19, 127.80 and 31.08

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Solution

The fourth proportional to 85.19, 127.80 and 31.08 is: 46.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.19 : 127.80 = 31.08 : x
  2. Step 2: Convert to fraction form
    85.19/127.80 = 31.08/x
  3. Step 3: Cross multiply
    85.19x = 127.80 × 31.08
  4. Step 4: Simplify right side
    85.19x = 3,972.02
  5. Step 5: Solve for x
    x = 3,972.02/85.19
  6. Step 6: Final answer
    x = 46.63

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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.