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Finding the Fourth Proportional to 280.79, 420.98 and 143.72

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Solution

The fourth proportional to 280.79, 420.98 and 143.72 is: 215.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.79 : 420.98 = 143.72 : x
  2. Step 2: Convert to fraction form
    280.79/420.98 = 143.72/x
  3. Step 3: Cross multiply
    280.79x = 420.98 × 143.72
  4. Step 4: Simplify right side
    280.79x = 60,500.42
  5. Step 5: Solve for x
    x = 60,500.42/280.79
  6. Step 6: Final answer
    x = 215.47

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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.