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Finding the Fourth Proportional to 403.21, 556.75 and 309.81

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Solution

The fourth proportional to 403.21, 556.75 and 309.81 is: 427.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    403.21 : 556.75 = 309.81 : x
  2. Step 2: Convert to fraction form
    403.21/556.75 = 309.81/x
  3. Step 3: Cross multiply
    403.21x = 556.75 × 309.81
  4. Step 4: Simplify right side
    403.21x = 172,489.19
  5. Step 5: Solve for x
    x = 172,489.19/403.21
  6. Step 6: Final answer
    x = 427.79

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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.