Question

3. Find the area of the triangle formed by joining the mid-points of triangle whose vertices are (0,-1), (2, 1) and (0, 3). Find the ratio of this area to the area of hegiven triangle.

Answer 1

Use the formula
$1 \div 2(x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2)) \:$

where x1 = 0
y1=-1
x2=2
y2=1
x3=0
y3=3
and you'll get your answer in sq. units . In case if the area is negative , suppose -150 sq. , then just take the integer value , i.e. 150 . Or if the answer is 0 , then the 3 given points are collinear and do not form any triangle .