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Finding the Fourth Proportional to 818.10, 1,128.90 and 486.60

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Solution

The fourth proportional to 818.10, 1,128.90 and 486.60 is: 671.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.10 : 1,128.90 = 486.60 : x
  2. Step 2: Convert to fraction form
    818.10/1,128.90 = 486.60/x
  3. Step 3: Cross multiply
    818.10x = 1,128.90 × 486.60
  4. Step 4: Simplify right side
    818.10x = 549,322.74
  5. Step 5: Solve for x
    x = 549,322.74/818.10
  6. Step 6: Final answer
    x = 671.46

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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.