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Finding the Fourth Proportional to 818.48, 1,128.66 and 720.20

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Solution

The fourth proportional to 818.48, 1,128.66 and 720.20 is: 993.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.48 : 1,128.66 = 720.20 : x
  2. Step 2: Convert to fraction form
    818.48/1,128.66 = 720.20/x
  3. Step 3: Cross multiply
    818.48x = 1,128.66 × 720.20
  4. Step 4: Simplify right side
    818.48x = 812,860.93
  5. Step 5: Solve for x
    x = 812,860.93/818.48
  6. Step 6: Final answer
    x = 993.13

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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.