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Finding the Fourth Proportional to 816.80, 1,127.10 and 485.16

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Solution

The fourth proportional to 816.80, 1,127.10 and 485.16 is: 669.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.80 : 1,127.10 = 485.16 : x
  2. Step 2: Convert to fraction form
    816.80/1,127.10 = 485.16/x
  3. Step 3: Cross multiply
    816.80x = 1,127.10 × 485.16
  4. Step 4: Simplify right side
    816.80x = 546,823.84
  5. Step 5: Solve for x
    x = 546,823.84/816.80
  6. Step 6: Final answer
    x = 669.47

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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.