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Finding the Fourth Proportional to 453.20, 679.80 and 420.80

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Solution

The fourth proportional to 453.20, 679.80 and 420.80 is: 631.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    453.20 : 679.80 = 420.80 : x
  2. Step 2: Convert to fraction form
    453.20/679.80 = 420.80/x
  3. Step 3: Cross multiply
    453.20x = 679.80 × 420.80
  4. Step 4: Simplify right side
    453.20x = 286,059.84
  5. Step 5: Solve for x
    x = 286,059.84/453.20
  6. Step 6: Final answer
    x = 631.20

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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.