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Finding the Fourth Proportional to 645.19, 890.36 and 383.21

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Solution

The fourth proportional to 645.19, 890.36 and 383.21 is: 528.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.19 : 890.36 = 383.21 : x
  2. Step 2: Convert to fraction form
    645.19/890.36 = 383.21/x
  3. Step 3: Cross multiply
    645.19x = 890.36 × 383.21
  4. Step 4: Simplify right side
    645.19x = 341,192.94
  5. Step 5: Solve for x
    x = 341,192.94/645.19
  6. Step 6: Final answer
    x = 528.83

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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.