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Finding the Fourth Proportional to 645.80, 891.68 and 480.40

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Solution

The fourth proportional to 645.80, 891.68 and 480.40 is: 663.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.80 : 891.68 = 480.40 : x
  2. Step 2: Convert to fraction form
    645.80/891.68 = 480.40/x
  3. Step 3: Cross multiply
    645.80x = 891.68 × 480.40
  4. Step 4: Simplify right side
    645.80x = 428,363.07
  5. Step 5: Solve for x
    x = 428,363.07/645.80
  6. Step 6: Final answer
    x = 663.31

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.