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Finding the Fourth Proportional to 783.82, 1,080.39 and 643.69

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Solution

The fourth proportional to 783.82, 1,080.39 and 643.69 is: 887.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    783.82 : 1,080.39 = 643.69 : x
  2. Step 2: Convert to fraction form
    783.82/1,080.39 = 643.69/x
  3. Step 3: Cross multiply
    783.82x = 1,080.39 × 643.69
  4. Step 4: Simplify right side
    783.82x = 695,436.24
  5. Step 5: Solve for x
    x = 695,436.24/783.82
  6. Step 6: Final answer
    x = 887.24

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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.