13. A is the point (−6,7),B is the point (−2,7) and C is the point (1,1).(a) Quadrilateral ABCD has rotational symmetry about the midpoint of AC. Find the coordinates of D.(b) Find the equation of(i) AB,(ii) AD.(c) Find the coordinates of the point where AD cuts the (−6,7),B1-axis.
Q. 13. A is the point (−6,7),B is the point (−2,7) and C is the point (1,1).(a) Quadrilateral ABCD has rotational symmetry about the midpoint of AC. Find the coordinates of D.(b) Find the equation of(i) AB,(ii) AD.(c) Find the coordinates of the point where AD cuts the (−6,7),B1-axis.
Calculate Midpoint of AC: Calculate the midpoint of AC.Midpoint formula: ((x1+x2)/2,(y1+y2)/2).Midpoint of AC = ((−6+1)/2,(7+1)/2)=(−5/2,8/2)=(−2.5,4).
Find Coordinates of D: Find the coordinates of D using rotational symmetry about the midpoint of AC.Point B is 4.5 units to the right and 3 units up from the midpoint.So, D will be 4.5 units to the left and 3 units down from the midpoint.Coordinates of D = (−2.5−4.5,4−3)=(−7,1).
Equation of AB: Find the equation of AB.Both A and B have the same y-coordinate, so AB is a horizontal line.Equation of a horizontal line: y=k, where k is the y-coordinate.Equation of AB: y=7.
Equation of AD: Find the equation of AD.Slope formula: (y2−y1)/(x2−x1).Slope of AD = (1−7)/(1−(−6))=−6/7.Point-slope form: y−y1=m(x−x1).Equation of AD: y−7=(−6/7)(x+6).
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