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Finding the Fourth Proportional to 280.53, 421.20 and 172.80

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Solution

The fourth proportional to 280.53, 421.20 and 172.80 is: 259.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.53 : 421.20 = 172.80 : x
  2. Step 2: Convert to fraction form
    280.53/421.20 = 172.80/x
  3. Step 3: Cross multiply
    280.53x = 421.20 × 172.80
  4. Step 4: Simplify right side
    280.53x = 72,783.36
  5. Step 5: Solve for x
    x = 72,783.36/280.53
  6. Step 6: Final answer
    x = 259.45

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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.