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Finding the Fourth Proportional to 858.88, 1,287.68 and 772

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Solution

The fourth proportional to 858.88, 1,287.68 and 772 is: 1,157.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.88 : 1,287.68 = 772 : x
  2. Step 2: Convert to fraction form
    858.88/1,287.68 = 772/x
  3. Step 3: Cross multiply
    858.88x = 1,287.68 × 772
  4. Step 4: Simplify right side
    858.88x = 994,088.96
  5. Step 5: Solve for x
    x = 994,088.96/858.88
  6. Step 6: Final answer
    x = 1,157.42

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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.