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Finding the Fourth Proportional to 280.88, 420 and 215.12

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Solution

The fourth proportional to 280.88, 420 and 215.12 is: 321.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.88 : 420 = 215.12 : x
  2. Step 2: Convert to fraction form
    280.88/420 = 215.12/x
  3. Step 3: Cross multiply
    280.88x = 420 × 215.12
  4. Step 4: Simplify right side
    280.88x = 90,350.40
  5. Step 5: Solve for x
    x = 90,350.40/280.88
  6. Step 6: Final answer
    x = 321.67

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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.