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Finding the Fourth Proportional to 858.64, 1,287.66 and 419.56

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Solution

The fourth proportional to 858.64, 1,287.66 and 419.56 is: 629.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.64 : 1,287.66 = 419.56 : x
  2. Step 2: Convert to fraction form
    858.64/1,287.66 = 419.56/x
  3. Step 3: Cross multiply
    858.64x = 1,287.66 × 419.56
  4. Step 4: Simplify right side
    858.64x = 540,250.63
  5. Step 5: Solve for x
    x = 540,250.63/858.64
  6. Step 6: Final answer
    x = 629.19

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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.