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Finding the Fourth Proportional to 85.16, 128.19 and 65.12

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Solution

The fourth proportional to 85.16, 128.19 and 65.12 is: 98.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.16 : 128.19 = 65.12 : x
  2. Step 2: Convert to fraction form
    85.16/128.19 = 65.12/x
  3. Step 3: Cross multiply
    85.16x = 128.19 × 65.12
  4. Step 4: Simplify right side
    85.16x = 8,347.73
  5. Step 5: Solve for x
    x = 8,347.73/85.16
  6. Step 6: Final answer
    x = 98.02

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.