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Finding the Fourth Proportional to 818.20, 1,128.34 and 631.39

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Solution

The fourth proportional to 818.20, 1,128.34 and 631.39 is: 870.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.20 : 1,128.34 = 631.39 : x
  2. Step 2: Convert to fraction form
    818.20/1,128.34 = 631.39/x
  3. Step 3: Cross multiply
    818.20x = 1,128.34 × 631.39
  4. Step 4: Simplify right side
    818.20x = 712,422.59
  5. Step 5: Solve for x
    x = 712,422.59/818.20
  6. Step 6: Final answer
    x = 870.72

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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.