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Finding the Fourth Proportional to 100.20, 138.30 and 65.22

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Solution

The fourth proportional to 100.20, 138.30 and 65.22 is: 90.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.20 : 138.30 = 65.22 : x
  2. Step 2: Convert to fraction form
    100.20/138.30 = 65.22/x
  3. Step 3: Cross multiply
    100.20x = 138.30 × 65.22
  4. Step 4: Simplify right side
    100.20x = 9,019.93
  5. Step 5: Solve for x
    x = 9,019.93/100.20
  6. Step 6: Final answer
    x = 90.02

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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.