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Finding the Fourth Proportional to 858.21, 1,287.78 and 447.69

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Solution

The fourth proportional to 858.21, 1,287.78 and 447.69 is: 671.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.21 : 1,287.78 = 447.69 : x
  2. Step 2: Convert to fraction form
    858.21/1,287.78 = 447.69/x
  3. Step 3: Cross multiply
    858.21x = 1,287.78 × 447.69
  4. Step 4: Simplify right side
    858.21x = 576,526.23
  5. Step 5: Solve for x
    x = 576,526.23/858.21
  6. Step 6: Final answer
    x = 671.78

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1.5x scale

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.