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Finding the Fourth Proportional to 85.80, 118.20 and 72.84

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Solution

The fourth proportional to 85.80, 118.20 and 72.84 is: 100.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.80 : 118.20 = 72.84 : x
  2. Step 2: Convert to fraction form
    85.80/118.20 = 72.84/x
  3. Step 3: Cross multiply
    85.80x = 118.20 × 72.84
  4. Step 4: Simplify right side
    85.80x = 8,609.69
  5. Step 5: Solve for x
    x = 8,609.69/85.80
  6. Step 6: Final answer
    x = 100.35

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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.