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Finding the Fourth Proportional to 811.17, 1,216.75 and 666.58

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Solution

The fourth proportional to 811.17, 1,216.75 and 666.58 is: 999.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.17 : 1,216.75 = 666.58 : x
  2. Step 2: Convert to fraction form
    811.17/1,216.75 = 666.58/x
  3. Step 3: Cross multiply
    811.17x = 1,216.75 × 666.58
  4. Step 4: Simplify right side
    811.17x = 811,061.22
  5. Step 5: Solve for x
    x = 811,061.22/811.17
  6. Step 6: Final answer
    x = 999.87

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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.