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Finding the Fourth Proportional to 839.79, 1,159.05 and 485.65

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Solution

The fourth proportional to 839.79, 1,159.05 and 485.65 is: 670.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.79 : 1,159.05 = 485.65 : x
  2. Step 2: Convert to fraction form
    839.79/1,159.05 = 485.65/x
  3. Step 3: Cross multiply
    839.79x = 1,159.05 × 485.65
  4. Step 4: Simplify right side
    839.79x = 562,890.40
  5. Step 5: Solve for x
    x = 562,890.40/839.79
  6. Step 6: Final answer
    x = 670.28

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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.