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Finding the Fourth Proportional to 102.66, 153.90 and 79.80

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Solution

The fourth proportional to 102.66, 153.90 and 79.80 is: 119.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.66 : 153.90 = 79.80 : x
  2. Step 2: Convert to fraction form
    102.66/153.90 = 79.80/x
  3. Step 3: Cross multiply
    102.66x = 153.90 × 79.80
  4. Step 4: Simplify right side
    102.66x = 12,281.22
  5. Step 5: Solve for x
    x = 12,281.22/102.66
  6. Step 6: Final answer
    x = 119.63

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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.