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Finding the Fourth Proportional to 389.76, 536.80 and 387.60

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Solution

The fourth proportional to 389.76, 536.80 and 387.60 is: 533.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.76 : 536.80 = 387.60 : x
  2. Step 2: Convert to fraction form
    389.76/536.80 = 387.60/x
  3. Step 3: Cross multiply
    389.76x = 536.80 × 387.60
  4. Step 4: Simplify right side
    389.76x = 208,063.68
  5. Step 5: Solve for x
    x = 208,063.68/389.76
  6. Step 6: Final answer
    x = 533.83

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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.