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Finding the Fourth Proportional to 260.66, 390.90 and 78.06

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Solution

The fourth proportional to 260.66, 390.90 and 78.06 is: 117.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    260.66 : 390.90 = 78.06 : x
  2. Step 2: Convert to fraction form
    260.66/390.90 = 78.06/x
  3. Step 3: Cross multiply
    260.66x = 390.90 × 78.06
  4. Step 4: Simplify right side
    260.66x = 30,513.65
  5. Step 5: Solve for x
    x = 30,513.65/260.66
  6. Step 6: Final answer
    x = 117.06

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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.