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Finding the Fourth Proportional to 809.40, 1,115.82 and 764.76

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Solution

The fourth proportional to 809.40, 1,115.82 and 764.76 is: 1,054.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.40 : 1,115.82 = 764.76 : x
  2. Step 2: Convert to fraction form
    809.40/1,115.82 = 764.76/x
  3. Step 3: Cross multiply
    809.40x = 1,115.82 × 764.76
  4. Step 4: Simplify right side
    809.40x = 853,334.50
  5. Step 5: Solve for x
    x = 853,334.50/809.40
  6. Step 6: Final answer
    x = 1,054.28

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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.