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Finding the Fourth Proportional to 718.35, 990.71 and 645.45

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Solution

The fourth proportional to 718.35, 990.71 and 645.45 is: 890.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.35 : 990.71 = 645.45 : x
  2. Step 2: Convert to fraction form
    718.35/990.71 = 645.45/x
  3. Step 3: Cross multiply
    718.35x = 990.71 × 645.45
  4. Step 4: Simplify right side
    718.35x = 639,453.00
  5. Step 5: Solve for x
    x = 639,453.00/718.35
  6. Step 6: Final answer
    x = 890.17

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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.