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Finding the Fourth Proportional to 279.99, 420.12 and 135.81

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Solution

The fourth proportional to 279.99, 420.12 and 135.81 is: 203.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.99 : 420.12 = 135.81 : x
  2. Step 2: Convert to fraction form
    279.99/420.12 = 135.81/x
  3. Step 3: Cross multiply
    279.99x = 420.12 × 135.81
  4. Step 4: Simplify right side
    279.99x = 57,056.50
  5. Step 5: Solve for x
    x = 57,056.50/279.99
  6. Step 6: Final answer
    x = 203.78

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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.