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Finding the Fourth Proportional to 485.71, 670.21 and 289.22

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Solution

The fourth proportional to 485.71, 670.21 and 289.22 is: 399.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.71 : 670.21 = 289.22 : x
  2. Step 2: Convert to fraction form
    485.71/670.21 = 289.22/x
  3. Step 3: Cross multiply
    485.71x = 670.21 × 289.22
  4. Step 4: Simplify right side
    485.71x = 193,838.14
  5. Step 5: Solve for x
    x = 193,838.14/485.71
  6. Step 6: Final answer
    x = 399.08

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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.