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Finding the Fourth Proportional to 818.39, 1,128.60 and 621.56

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Solution

The fourth proportional to 818.39, 1,128.60 and 621.56 is: 857.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.39 : 1,128.60 = 621.56 : x
  2. Step 2: Convert to fraction form
    818.39/1,128.60 = 621.56/x
  3. Step 3: Cross multiply
    818.39x = 1,128.60 × 621.56
  4. Step 4: Simplify right side
    818.39x = 701,489.51
  5. Step 5: Solve for x
    x = 701,489.51/818.39
  6. Step 6: Final answer
    x = 857.16

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Double scale
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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.