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Finding the Fourth Proportional to 280.40, 420.65 and 164.86

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Solution

The fourth proportional to 280.40, 420.65 and 164.86 is: 247.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.40 : 420.65 = 164.86 : x
  2. Step 2: Convert to fraction form
    280.40/420.65 = 164.86/x
  3. Step 3: Cross multiply
    280.40x = 420.65 × 164.86
  4. Step 4: Simplify right side
    280.40x = 69,348.36
  5. Step 5: Solve for x
    x = 69,348.36/280.40
  6. Step 6: Final answer
    x = 247.32

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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.