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Finding the Fourth Proportional to 811.25, 1,215.72 and 400.68

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Solution

The fourth proportional to 811.25, 1,215.72 and 400.68 is: 600.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.25 : 1,215.72 = 400.68 : x
  2. Step 2: Convert to fraction form
    811.25/1,215.72 = 400.68/x
  3. Step 3: Cross multiply
    811.25x = 1,215.72 × 400.68
  4. Step 4: Simplify right side
    811.25x = 487,114.69
  5. Step 5: Solve for x
    x = 487,114.69/811.25
  6. Step 6: Final answer
    x = 600.45

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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.