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Finding the Fourth Proportional to 656.80, 985.20 and 272.80

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Solution

The fourth proportional to 656.80, 985.20 and 272.80 is: 409.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    656.80 : 985.20 = 272.80 : x
  2. Step 2: Convert to fraction form
    656.80/985.20 = 272.80/x
  3. Step 3: Cross multiply
    656.80x = 985.20 × 272.80
  4. Step 4: Simplify right side
    656.80x = 268,762.56
  5. Step 5: Solve for x
    x = 268,762.56/656.80
  6. Step 6: Final answer
    x = 409.20

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.