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Finding the Fourth Proportional to 100.02, 138.07 and 78.25

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Solution

The fourth proportional to 100.02, 138.07 and 78.25 is: 108.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.02 : 138.07 = 78.25 : x
  2. Step 2: Convert to fraction form
    100.02/138.07 = 78.25/x
  3. Step 3: Cross multiply
    100.02x = 138.07 × 78.25
  4. Step 4: Simplify right side
    100.02x = 10,803.98
  5. Step 5: Solve for x
    x = 10,803.98/100.02
  6. Step 6: Final answer
    x = 108.02

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.