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Finding the Fourth Proportional to 860.69, 1,185.80 and 647.06

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Solution

The fourth proportional to 860.69, 1,185.80 and 647.06 is: 891.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.69 : 1,185.80 = 647.06 : x
  2. Step 2: Convert to fraction form
    860.69/1,185.80 = 647.06/x
  3. Step 3: Cross multiply
    860.69x = 1,185.80 × 647.06
  4. Step 4: Simplify right side
    860.69x = 767,274.58
  5. Step 5: Solve for x
    x = 767,274.58/860.69
  6. Step 6: Final answer
    x = 891.47

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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.