# two points A(-3,2) and B(4,-1) are shown on a diagram. plot the two suitable points C and D so that ABCD is a parallelogram. Label the points.

justaguide | College Teacher | (Level 2) Distinguished Educator

Posted on

A parallelogram ABCD has 4 sides with AB parallel to CD and BC parallel to DA. Also, the parallel sides are equal in length.

The slope of the line joining A(-3,2) and B(4,-1) is (2 + 1)/(-3 - 4) = 3/-7

The slope of CD should be -3/7.

Points AB are at a distance sqrt((-3-4)^2 + (2+1)^2) = sqrt(49+9) = sqrt 58 from each other. The points C and D have to lie on a line with a slope -3/7 and can be placed anywhere on the line subject to the condition that the distance between them is sqrt 58.

The required points C and D can be any two points at a distance sqrt 58 from each other and which are on a line with slope -3/7.

parvesh | Student, Grade 11 | (Level 1) eNoter

Posted on

the two lines that will be drawn from a and b will have equal slope

because lines are parallel and line CD will have slope equal to AB

solve using    (y-y1)=y2-y1/x2-x1(x-x1)