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Finding the Fourth Proportional to 280.61, 420.99 and 143.75

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Solution

The fourth proportional to 280.61, 420.99 and 143.75 is: 215.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.61 : 420.99 = 143.75 : x
  2. Step 2: Convert to fraction form
    280.61/420.99 = 143.75/x
  3. Step 3: Cross multiply
    280.61x = 420.99 × 143.75
  4. Step 4: Simplify right side
    280.61x = 60,516.17
  5. Step 5: Solve for x
    x = 60,516.17/280.61
  6. Step 6: Final answer
    x = 215.66

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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.