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Finding the Fourth Proportional to 159.30, 239.10 and 78.21

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Solution

The fourth proportional to 159.30, 239.10 and 78.21 is: 117.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    159.30 : 239.10 = 78.21 : x
  2. Step 2: Convert to fraction form
    159.30/239.10 = 78.21/x
  3. Step 3: Cross multiply
    159.30x = 239.10 × 78.21
  4. Step 4: Simplify right side
    159.30x = 18,700.01
  5. Step 5: Solve for x
    x = 18,700.01/159.30
  6. Step 6: Final answer
    x = 117.39

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.