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Finding the Fourth Proportional to 928.39, 1,278.15 and 811.88

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Solution

The fourth proportional to 928.39, 1,278.15 and 811.88 is: 1,117.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.39 : 1,278.15 = 811.88 : x
  2. Step 2: Convert to fraction form
    928.39/1,278.15 = 811.88/x
  3. Step 3: Cross multiply
    928.39x = 1,278.15 × 811.88
  4. Step 4: Simplify right side
    928.39x = 1,037,704.42
  5. Step 5: Solve for x
    x = 1,037,704.42/928.39
  6. Step 6: Final answer
    x = 1,117.75

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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.