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Finding the Fourth Proportional to 115.21, 158.93 and 78.42

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Solution

The fourth proportional to 115.21, 158.93 and 78.42 is: 108.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.21 : 158.93 = 78.42 : x
  2. Step 2: Convert to fraction form
    115.21/158.93 = 78.42/x
  3. Step 3: Cross multiply
    115.21x = 158.93 × 78.42
  4. Step 4: Simplify right side
    115.21x = 12,463.34
  5. Step 5: Solve for x
    x = 12,463.34/115.21
  6. Step 6: Final answer
    x = 108.18

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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.