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Finding the Fourth Proportional to 121.95, 183.23 and 78.64

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Solution

The fourth proportional to 121.95, 183.23 and 78.64 is: 118.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.95 : 183.23 = 78.64 : x
  2. Step 2: Convert to fraction form
    121.95/183.23 = 78.64/x
  3. Step 3: Cross multiply
    121.95x = 183.23 × 78.64
  4. Step 4: Simplify right side
    121.95x = 14,409.21
  5. Step 5: Solve for x
    x = 14,409.21/121.95
  6. Step 6: Final answer
    x = 118.16

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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.