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Finding the Fourth Proportional to 85.12, 127.80 and 53.20

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Solution

The fourth proportional to 85.12, 127.80 and 53.20 is: 79.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.12 : 127.80 = 53.20 : x
  2. Step 2: Convert to fraction form
    85.12/127.80 = 53.20/x
  3. Step 3: Cross multiply
    85.12x = 127.80 × 53.20
  4. Step 4: Simplify right side
    85.12x = 6,798.96
  5. Step 5: Solve for x
    x = 6,798.96/85.12
  6. Step 6: Final answer
    x = 79.88

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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.