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Finding the Fourth Proportional to 818.10, 1,128.69 and 621.18

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Solution

The fourth proportional to 818.10, 1,128.69 and 621.18 is: 857.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.10 : 1,128.69 = 621.18 : x
  2. Step 2: Convert to fraction form
    818.10/1,128.69 = 621.18/x
  3. Step 3: Cross multiply
    818.10x = 1,128.69 × 621.18
  4. Step 4: Simplify right side
    818.10x = 701,119.65
  5. Step 5: Solve for x
    x = 701,119.65/818.10
  6. Step 6: Final answer
    x = 857.01

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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.