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Finding the Fourth Proportional to 815.16, 1,222.90 and 328.21

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Solution

The fourth proportional to 815.16, 1,222.90 and 328.21 is: 492.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.16 : 1,222.90 = 328.21 : x
  2. Step 2: Convert to fraction form
    815.16/1,222.90 = 328.21/x
  3. Step 3: Cross multiply
    815.16x = 1,222.90 × 328.21
  4. Step 4: Simplify right side
    815.16x = 401,361.89
  5. Step 5: Solve for x
    x = 401,361.89/815.16
  6. Step 6: Final answer
    x = 492.37

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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.