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Finding the Fourth Proportional to 645.40, 890.65 and 383.42

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Solution

The fourth proportional to 645.40, 890.65 and 383.42 is: 529.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.40 : 890.65 = 383.42 : x
  2. Step 2: Convert to fraction form
    645.40/890.65 = 383.42/x
  3. Step 3: Cross multiply
    645.40x = 890.65 × 383.42
  4. Step 4: Simplify right side
    645.40x = 341,490.72
  5. Step 5: Solve for x
    x = 341,490.72/645.40
  6. Step 6: Final answer
    x = 529.11

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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.