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Finding the Fourth Proportional to 280.56, 420.88 and 172.20

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Solution

The fourth proportional to 280.56, 420.88 and 172.20 is: 258.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.56 : 420.88 = 172.20 : x
  2. Step 2: Convert to fraction form
    280.56/420.88 = 172.20/x
  3. Step 3: Cross multiply
    280.56x = 420.88 × 172.20
  4. Step 4: Simplify right side
    280.56x = 72,475.54
  5. Step 5: Solve for x
    x = 72,475.54/280.56
  6. Step 6: Final answer
    x = 258.32

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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.