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Finding the Fourth Proportional to 260.64, 391.20 and 212.80

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Solution

The fourth proportional to 260.64, 391.20 and 212.80 is: 319.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    260.64 : 391.20 = 212.80 : x
  2. Step 2: Convert to fraction form
    260.64/391.20 = 212.80/x
  3. Step 3: Cross multiply
    260.64x = 391.20 × 212.80
  4. Step 4: Simplify right side
    260.64x = 83,247.36
  5. Step 5: Solve for x
    x = 83,247.36/260.64
  6. Step 6: Final answer
    x = 319.40

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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.