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Finding the Fourth Proportional to 280.51, 420.21 and 212.11

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Solution

The fourth proportional to 280.51, 420.21 and 212.11 is: 317.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.51 : 420.21 = 212.11 : x
  2. Step 2: Convert to fraction form
    280.51/420.21 = 212.11/x
  3. Step 3: Cross multiply
    280.51x = 420.21 × 212.11
  4. Step 4: Simplify right side
    280.51x = 89,130.74
  5. Step 5: Solve for x
    x = 89,130.74/280.51
  6. Step 6: Final answer
    x = 317.75

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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.