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Finding the Fourth Proportional to 79.58, 109.57 and 72.74

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Solution

The fourth proportional to 79.58, 109.57 and 72.74 is: 100.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.58 : 109.57 = 72.74 : x
  2. Step 2: Convert to fraction form
    79.58/109.57 = 72.74/x
  3. Step 3: Cross multiply
    79.58x = 109.57 × 72.74
  4. Step 4: Simplify right side
    79.58x = 7,970.12
  5. Step 5: Solve for x
    x = 7,970.12/79.58
  6. Step 6: Final answer
    x = 100.15

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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.