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Finding the Fourth Proportional to 858.60, 1,279.80 and 822.15

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Solution

The fourth proportional to 858.60, 1,279.80 and 822.15 is: 1,225.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.60 : 1,279.80 = 822.15 : x
  2. Step 2: Convert to fraction form
    858.60/1,279.80 = 822.15/x
  3. Step 3: Cross multiply
    858.60x = 1,279.80 × 822.15
  4. Step 4: Simplify right side
    858.60x = 1,052,187.57
  5. Step 5: Solve for x
    x = 1,052,187.57/858.60
  6. Step 6: Final answer
    x = 1,225.47

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.