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Finding the Fourth Proportional to 79.20, 118.80 and 45

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Solution

The fourth proportional to 79.20, 118.80 and 45 is: 67.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.20 : 118.80 = 45 : x
  2. Step 2: Convert to fraction form
    79.20/118.80 = 45/x
  3. Step 3: Cross multiply
    79.20x = 118.80 × 45
  4. Step 4: Simplify right side
    79.20x = 5,346
  5. Step 5: Solve for x
    x = 5,346/79.20
  6. Step 6: Final answer
    x = 67.50

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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.