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Finding the Fourth Proportional to 810.90, 1,216.80 and 445.68

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Solution

The fourth proportional to 810.90, 1,216.80 and 445.68 is: 668.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.90 : 1,216.80 = 445.68 : x
  2. Step 2: Convert to fraction form
    810.90/1,216.80 = 445.68/x
  3. Step 3: Cross multiply
    810.90x = 1,216.80 × 445.68
  4. Step 4: Simplify right side
    810.90x = 542,303.42
  5. Step 5: Solve for x
    x = 542,303.42/810.90
  6. Step 6: Final answer
    x = 668.77

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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.