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Finding the Fourth Proportional to 455.28, 679.62 and 420.99

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Solution

The fourth proportional to 455.28, 679.62 and 420.99 is: 628.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    455.28 : 679.62 = 420.99 : x
  2. Step 2: Convert to fraction form
    455.28/679.62 = 420.99/x
  3. Step 3: Cross multiply
    455.28x = 679.62 × 420.99
  4. Step 4: Simplify right side
    455.28x = 286,113.22
  5. Step 5: Solve for x
    x = 286,113.22/455.28
  6. Step 6: Final answer
    x = 628.43

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.