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Finding the Fourth Proportional to 320.80, 442.60 and 210.40

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Solution

The fourth proportional to 320.80, 442.60 and 210.40 is: 290.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    320.80 : 442.60 = 210.40 : x
  2. Step 2: Convert to fraction form
    320.80/442.60 = 210.40/x
  3. Step 3: Cross multiply
    320.80x = 442.60 × 210.40
  4. Step 4: Simplify right side
    320.80x = 93,123.04
  5. Step 5: Solve for x
    x = 93,123.04/320.80
  6. Step 6: Final answer
    x = 290.28

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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.