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Finding the Fourth Proportional to 421.02, 631.34 and 215.70

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Solution

The fourth proportional to 421.02, 631.34 and 215.70 is: 323.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.02 : 631.34 = 215.70 : x
  2. Step 2: Convert to fraction form
    421.02/631.34 = 215.70/x
  3. Step 3: Cross multiply
    421.02x = 631.34 × 215.70
  4. Step 4: Simplify right side
    421.02x = 136,180.04
  5. Step 5: Solve for x
    x = 136,180.04/421.02
  6. Step 6: Final answer
    x = 323.45

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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.