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Finding the Fourth Proportional to 645.40, 890.80 and 383.56

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Solution

The fourth proportional to 645.40, 890.80 and 383.56 is: 529.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.40 : 890.80 = 383.56 : x
  2. Step 2: Convert to fraction form
    645.40/890.80 = 383.56/x
  3. Step 3: Cross multiply
    645.40x = 890.80 × 383.56
  4. Step 4: Simplify right side
    645.40x = 341,675.25
  5. Step 5: Solve for x
    x = 341,675.25/645.40
  6. Step 6: Final answer
    x = 529.40

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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.