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Finding the Fourth Proportional to 280.35, 386.90 and 210.56

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Solution

The fourth proportional to 280.35, 386.90 and 210.56 is: 290.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.35 : 386.90 = 210.56 : x
  2. Step 2: Convert to fraction form
    280.35/386.90 = 210.56/x
  3. Step 3: Cross multiply
    280.35x = 386.90 × 210.56
  4. Step 4: Simplify right side
    280.35x = 81,462.68
  5. Step 5: Solve for x
    x = 81,462.68/280.35
  6. Step 6: Final answer
    x = 290.57

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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.