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Finding the Fourth Proportional to 816.45, 1,126.40 and 640.10

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Solution

The fourth proportional to 816.45, 1,126.40 and 640.10 is: 883.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.45 : 1,126.40 = 640.10 : x
  2. Step 2: Convert to fraction form
    816.45/1,126.40 = 640.10/x
  3. Step 3: Cross multiply
    816.45x = 1,126.40 × 640.10
  4. Step 4: Simplify right side
    816.45x = 720,999.81
  5. Step 5: Solve for x
    x = 720,999.81/816.45
  6. Step 6: Final answer
    x = 883.09

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.