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Finding the Fourth Proportional to 818.28, 1,128.36 and 643.32

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Solution

The fourth proportional to 818.28, 1,128.36 and 643.32 is: 887.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.28 : 1,128.36 = 643.32 : x
  2. Step 2: Convert to fraction form
    818.28/1,128.36 = 643.32/x
  3. Step 3: Cross multiply
    818.28x = 1,128.36 × 643.32
  4. Step 4: Simplify right side
    818.28x = 725,896.56
  5. Step 5: Solve for x
    x = 725,896.56/818.28
  6. Step 6: Final answer
    x = 887.10

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1.5x scale

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.