In parallelogram ABCD, side BC is 6 times larger than side AB. Bisectors of angles DAB and ABC intersect line CD
In parallelogram ABCD, side BC is 6 times larger than side AB. Bisectors of angles DAB and ABC intersect line CD at points M and N, respectively. Find the perimeter of parallelogram ABCD if MN = 22.
Since AM is the bisector of angle A, then the angle BAM = MAD, the angle BKA = KAD, both lying crosswise at the intersection of parallel straight lines BC and AD secant AK.
Angle MKC = BKA as vertical angles. Angle CMR = BАК as criss-crossing at the intersection of parallel AB and MN secant AM. Then the triangle KCM is isosceles KC = MC.
Similarly, triangle DPN is isosceles DP = DN.
Triangles ABK and BAP are isosceles, then AB = BK = AP, when and KC = PD, and therefore:
PD = DN = KC = MC.
By condition, BC = 6 * AB, and MN = 22 cm.
Then KS = DP = 5 * AB, which means DN = MC = 5 * AB.
Then MN = DN + CD + MC = 5 * AB + AB + 5 * AB = 22.
11 * AB = 22.
AB = 22/11 = 2 cm.
BC = 2 * 6 = 12 cm.
Then P = 2 * (2 + 12) = 28 cm.
Answer: The perimeter of the parallelogram is 28 cm.