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Finding the Fourth Proportional to 155.79, 215.00 and 85.86

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Solution

The fourth proportional to 155.79, 215.00 and 85.86 is: 118.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    155.79 : 215.00 = 85.86 : x
  2. Step 2: Convert to fraction form
    155.79/215.00 = 85.86/x
  3. Step 3: Cross multiply
    155.79x = 215.00 × 85.86
  4. Step 4: Simplify right side
    155.79x = 18,458.40
  5. Step 5: Solve for x
    x = 18,458.40/155.79
  6. Step 6: Final answer
    x = 118.48

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.