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Finding the Fourth Proportional to 783.68, 1,081.65 and 485.09

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Solution

The fourth proportional to 783.68, 1,081.65 and 485.09 is: 669.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    783.68 : 1,081.65 = 485.09 : x
  2. Step 2: Convert to fraction form
    783.68/1,081.65 = 485.09/x
  3. Step 3: Cross multiply
    783.68x = 1,081.65 × 485.09
  4. Step 4: Simplify right side
    783.68x = 524,698.07
  5. Step 5: Solve for x
    x = 524,698.07/783.68
  6. Step 6: Final answer
    x = 669.54

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1.5x scale

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.