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Finding the Fourth Proportional to 811.98, 1,215.68 and 631.49

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Solution

The fourth proportional to 811.98, 1,215.68 and 631.49 is: 945.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.98 : 1,215.68 = 631.49 : x
  2. Step 2: Convert to fraction form
    811.98/1,215.68 = 631.49/x
  3. Step 3: Cross multiply
    811.98x = 1,215.68 × 631.49
  4. Step 4: Simplify right side
    811.98x = 767,680.53
  5. Step 5: Solve for x
    x = 767,680.53/811.98
  6. Step 6: Final answer
    x = 945.44

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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.