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Finding the Fourth Proportional to 420.91, 630.95 and 215.57

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Solution

The fourth proportional to 420.91, 630.95 and 215.57 is: 323.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.91 : 630.95 = 215.57 : x
  2. Step 2: Convert to fraction form
    420.91/630.95 = 215.57/x
  3. Step 3: Cross multiply
    420.91x = 630.95 × 215.57
  4. Step 4: Simplify right side
    420.91x = 136,016.01
  5. Step 5: Solve for x
    x = 136,016.01/420.91
  6. Step 6: Final answer
    x = 323.15

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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.