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Finding the Fourth Proportional to 485.70, 669.93 and 289.05

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Solution

The fourth proportional to 485.70, 669.93 and 289.05 is: 398.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.70 : 669.93 = 289.05 : x
  2. Step 2: Convert to fraction form
    485.70/669.93 = 289.05/x
  3. Step 3: Cross multiply
    485.70x = 669.93 × 289.05
  4. Step 4: Simplify right side
    485.70x = 193,643.27
  5. Step 5: Solve for x
    x = 193,643.27/485.70
  6. Step 6: Final answer
    x = 398.69

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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.