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Finding the Fourth Proportional to 431.40, 649.84 and 388.68

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Solution

The fourth proportional to 431.40, 649.84 and 388.68 is: 585.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.40 : 649.84 = 388.68 : x
  2. Step 2: Convert to fraction form
    431.40/649.84 = 388.68/x
  3. Step 3: Cross multiply
    431.40x = 649.84 × 388.68
  4. Step 4: Simplify right side
    431.40x = 252,579.81
  5. Step 5: Solve for x
    x = 252,579.81/431.40
  6. Step 6: Final answer
    x = 585.49

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.