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Finding the Fourth Proportional to 260.79, 391.04 and 87.42

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Solution

The fourth proportional to 260.79, 391.04 and 87.42 is: 131.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    260.79 : 391.04 = 87.42 : x
  2. Step 2: Convert to fraction form
    260.79/391.04 = 87.42/x
  3. Step 3: Cross multiply
    260.79x = 391.04 × 87.42
  4. Step 4: Simplify right side
    260.79x = 34,184.28
  5. Step 5: Solve for x
    x = 34,184.28/260.79
  6. Step 6: Final answer
    x = 131.08

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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.