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Finding the Fourth Proportional to 91.80, 138.24 and 73.80

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Solution

The fourth proportional to 91.80, 138.24 and 73.80 is: 111.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.80 : 138.24 = 73.80 : x
  2. Step 2: Convert to fraction form
    91.80/138.24 = 73.80/x
  3. Step 3: Cross multiply
    91.80x = 138.24 × 73.80
  4. Step 4: Simplify right side
    91.80x = 10,202.11
  5. Step 5: Solve for x
    x = 10,202.11/91.80
  6. Step 6: Final answer
    x = 111.13

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.