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Finding the Fourth Proportional to 645.19, 890.71 and 505.01

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Solution

The fourth proportional to 645.19, 890.71 and 505.01 is: 697.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.19 : 890.71 = 505.01 : x
  2. Step 2: Convert to fraction form
    645.19/890.71 = 505.01/x
  3. Step 3: Cross multiply
    645.19x = 890.71 × 505.01
  4. Step 4: Simplify right side
    645.19x = 449,817.46
  5. Step 5: Solve for x
    x = 449,817.46/645.19
  6. Step 6: Final answer
    x = 697.19

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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.