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Finding the Fourth Proportional to 137.22, 189.36 and 78.21

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Solution

The fourth proportional to 137.22, 189.36 and 78.21 is: 107.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.22 : 189.36 = 78.21 : x
  2. Step 2: Convert to fraction form
    137.22/189.36 = 78.21/x
  3. Step 3: Cross multiply
    137.22x = 189.36 × 78.21
  4. Step 4: Simplify right side
    137.22x = 14,808.51
  5. Step 5: Solve for x
    x = 14,808.51/137.22
  6. Step 6: Final answer
    x = 107.92

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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.