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Finding the Fourth Proportional to 928.20, 1,281.38 and 717.90

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Solution

The fourth proportional to 928.20, 1,281.38 and 717.90 is: 991.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.20 : 1,281.38 = 717.90 : x
  2. Step 2: Convert to fraction form
    928.20/1,281.38 = 717.90/x
  3. Step 3: Cross multiply
    928.20x = 1,281.38 × 717.90
  4. Step 4: Simplify right side
    928.20x = 919,902.70
  5. Step 5: Solve for x
    x = 919,902.70/928.20
  6. Step 6: Final answer
    x = 991.06

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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.