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Finding the Fourth Proportional to 100.10, 138.08 and 65.10

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Solution

The fourth proportional to 100.10, 138.08 and 65.10 is: 89.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.10 : 138.08 = 65.10 : x
  2. Step 2: Convert to fraction form
    100.10/138.08 = 65.10/x
  3. Step 3: Cross multiply
    100.10x = 138.08 × 65.10
  4. Step 4: Simplify right side
    100.10x = 8,989.01
  5. Step 5: Solve for x
    x = 8,989.01/100.10
  6. Step 6: Final answer
    x = 89.80

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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.