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Finding the Fourth Proportional to 85.19, 117.52 and 72.78

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Solution

The fourth proportional to 85.19, 117.52 and 72.78 is: 100.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.19 : 117.52 = 72.78 : x
  2. Step 2: Convert to fraction form
    85.19/117.52 = 72.78/x
  3. Step 3: Cross multiply
    85.19x = 117.52 × 72.78
  4. Step 4: Simplify right side
    85.19x = 8,552.92
  5. Step 5: Solve for x
    x = 8,552.92/85.19
  6. Step 6: Final answer
    x = 100.40

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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.