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Finding the Fourth Proportional to 280.74, 420.71 and 215.49

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Solution

The fourth proportional to 280.74, 420.71 and 215.49 is: 322.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.74 : 420.71 = 215.49 : x
  2. Step 2: Convert to fraction form
    280.74/420.71 = 215.49/x
  3. Step 3: Cross multiply
    280.74x = 420.71 × 215.49
  4. Step 4: Simplify right side
    280.74x = 90,658.80
  5. Step 5: Solve for x
    x = 90,658.80/280.74
  6. Step 6: Final answer
    x = 322.93

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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.