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Finding the Fourth Proportional to 428.16, 645.96 and 380.64

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Solution

The fourth proportional to 428.16, 645.96 and 380.64 is: 574.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.16 : 645.96 = 380.64 : x
  2. Step 2: Convert to fraction form
    428.16/645.96 = 380.64/x
  3. Step 3: Cross multiply
    428.16x = 645.96 × 380.64
  4. Step 4: Simplify right side
    428.16x = 245,878.21
  5. Step 5: Solve for x
    x = 245,878.21/428.16
  6. Step 6: Final answer
    x = 574.27

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.