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Finding the Fourth Proportional to 253.90, 380.40 and 208.18

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Solution

The fourth proportional to 253.90, 380.40 and 208.18 is: 311.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    253.90 : 380.40 = 208.18 : x
  2. Step 2: Convert to fraction form
    253.90/380.40 = 208.18/x
  3. Step 3: Cross multiply
    253.90x = 380.40 × 208.18
  4. Step 4: Simplify right side
    253.90x = 79,191.67
  5. Step 5: Solve for x
    x = 79,191.67/253.90
  6. Step 6: Final answer
    x = 311.90

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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.