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Finding the Fourth Proportional to 858.84, 1,280.86 and 815.90

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Solution

The fourth proportional to 858.84, 1,280.86 and 815.90 is: 1,216.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.84 : 1,280.86 = 815.90 : x
  2. Step 2: Convert to fraction form
    858.84/1,280.86 = 815.90/x
  3. Step 3: Cross multiply
    858.84x = 1,280.86 × 815.90
  4. Step 4: Simplify right side
    858.84x = 1,045,053.67
  5. Step 5: Solve for x
    x = 1,045,053.67/858.84
  6. Step 6: Final answer
    x = 1,216.82

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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.