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Finding the Fourth Proportional to 100.10, 138.10 and 56.42

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Solution

The fourth proportional to 100.10, 138.10 and 56.42 is: 77.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.10 : 138.10 = 56.42 : x
  2. Step 2: Convert to fraction form
    100.10/138.10 = 56.42/x
  3. Step 3: Cross multiply
    100.10x = 138.10 × 56.42
  4. Step 4: Simplify right side
    100.10x = 7,791.81
  5. Step 5: Solve for x
    x = 7,791.81/100.10
  6. Step 6: Final answer
    x = 77.84

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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.