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Finding the Fourth Proportional to 79.97, 120 and 78.30

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Solution

The fourth proportional to 79.97, 120 and 78.30 is: 117.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.97 : 120 = 78.30 : x
  2. Step 2: Convert to fraction form
    79.97/120 = 78.30/x
  3. Step 3: Cross multiply
    79.97x = 120 × 78.30
  4. Step 4: Simplify right side
    79.97x = 9,396
  5. Step 5: Solve for x
    x = 9,396/79.97
  6. Step 6: Final answer
    x = 117.50

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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.