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Finding the Fourth Proportional to 811.12, 1,216.68 and 649.12

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Solution

The fourth proportional to 811.12, 1,216.68 and 649.12 is: 973.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.12 : 1,216.68 = 649.12 : x
  2. Step 2: Convert to fraction form
    811.12/1,216.68 = 649.12/x
  3. Step 3: Cross multiply
    811.12x = 1,216.68 × 649.12
  4. Step 4: Simplify right side
    811.12x = 789,771.32
  5. Step 5: Solve for x
    x = 789,771.32/811.12
  6. Step 6: Final answer
    x = 973.68

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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.