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Finding the Fourth Proportional to 85.62, 128.40 and 58.74

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Solution

The fourth proportional to 85.62, 128.40 and 58.74 is: 88.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.62 : 128.40 = 58.74 : x
  2. Step 2: Convert to fraction form
    85.62/128.40 = 58.74/x
  3. Step 3: Cross multiply
    85.62x = 128.40 × 58.74
  4. Step 4: Simplify right side
    85.62x = 7,542.22
  5. Step 5: Solve for x
    x = 7,542.22/85.62
  6. Step 6: Final answer
    x = 88.09

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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.