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Finding the Fourth Proportional to 85.98, 128.43 and 73.08

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Solution

The fourth proportional to 85.98, 128.43 and 73.08 is: 109.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.98 : 128.43 = 73.08 : x
  2. Step 2: Convert to fraction form
    85.98/128.43 = 73.08/x
  3. Step 3: Cross multiply
    85.98x = 128.43 × 73.08
  4. Step 4: Simplify right side
    85.98x = 9,385.66
  5. Step 5: Solve for x
    x = 9,385.66/85.98
  6. Step 6: Final answer
    x = 109.16

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.