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Finding the Fourth Proportional to 420.15, 627.81 and 320.77

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Solution

The fourth proportional to 420.15, 627.81 and 320.77 is: 479.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.15 : 627.81 = 320.77 : x
  2. Step 2: Convert to fraction form
    420.15/627.81 = 320.77/x
  3. Step 3: Cross multiply
    420.15x = 627.81 × 320.77
  4. Step 4: Simplify right side
    420.15x = 201,382.61
  5. Step 5: Solve for x
    x = 201,382.61/420.15
  6. Step 6: Final answer
    x = 479.31

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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.