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Finding the Fourth Proportional to 645.57, 890.78 and 365.78

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Solution

The fourth proportional to 645.57, 890.78 and 365.78 is: 504.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.57 : 890.78 = 365.78 : x
  2. Step 2: Convert to fraction form
    645.57/890.78 = 365.78/x
  3. Step 3: Cross multiply
    645.57x = 890.78 × 365.78
  4. Step 4: Simplify right side
    645.57x = 325,823.23
  5. Step 5: Solve for x
    x = 325,823.23/645.57
  6. Step 6: Final answer
    x = 504.71

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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.