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Finding the Fourth Proportional to 378.40, 522 and 320.80

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Solution

The fourth proportional to 378.40, 522 and 320.80 is: 442.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    378.40 : 522 = 320.80 : x
  2. Step 2: Convert to fraction form
    378.40/522 = 320.80/x
  3. Step 3: Cross multiply
    378.40x = 522 × 320.80
  4. Step 4: Simplify right side
    378.40x = 167,457.60
  5. Step 5: Solve for x
    x = 167,457.60/378.40
  6. Step 6: Final answer
    x = 442.54

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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.