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Finding the Fourth Proportional to 799.80, 1,200.39 and 312.99

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Solution

The fourth proportional to 799.80, 1,200.39 and 312.99 is: 469.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    799.80 : 1,200.39 = 312.99 : x
  2. Step 2: Convert to fraction form
    799.80/1,200.39 = 312.99/x
  3. Step 3: Cross multiply
    799.80x = 1,200.39 × 312.99
  4. Step 4: Simplify right side
    799.80x = 375,710.07
  5. Step 5: Solve for x
    x = 375,710.07/799.80
  6. Step 6: Final answer
    x = 469.76

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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.