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Finding the Fourth Proportional to 661.65, 990.40 and 455.01

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Solution

The fourth proportional to 661.65, 990.40 and 455.01 is: 681.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.65 : 990.40 = 455.01 : x
  2. Step 2: Convert to fraction form
    661.65/990.40 = 455.01/x
  3. Step 3: Cross multiply
    661.65x = 990.40 × 455.01
  4. Step 4: Simplify right side
    661.65x = 450,641.90
  5. Step 5: Solve for x
    x = 450,641.90/661.65
  6. Step 6: Final answer
    x = 681.09

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.