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Finding the Fourth Proportional to 420.16, 627.82 and 320.78

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Solution

The fourth proportional to 420.16, 627.82 and 320.78 is: 479.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.16 : 627.82 = 320.78 : x
  2. Step 2: Convert to fraction form
    420.16/627.82 = 320.78/x
  3. Step 3: Cross multiply
    420.16x = 627.82 × 320.78
  4. Step 4: Simplify right side
    420.16x = 201,392.10
  5. Step 5: Solve for x
    x = 201,392.10/420.16
  6. Step 6: Final answer
    x = 479.32

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.