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Finding the Fourth Proportional to 158.40, 218.64 and 100.20

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Solution

The fourth proportional to 158.40, 218.64 and 100.20 is: 138.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    158.40 : 218.64 = 100.20 : x
  2. Step 2: Convert to fraction form
    158.40/218.64 = 100.20/x
  3. Step 3: Cross multiply
    158.40x = 218.64 × 100.20
  4. Step 4: Simplify right side
    158.40x = 21,907.73
  5. Step 5: Solve for x
    x = 21,907.73/158.40
  6. Step 6: Final answer
    x = 138.31

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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.