answer
The pentagon MNPQR has a perimeter of 22 units.
Geometrically speaking, the perimeter of the pentagon is the sum of the lengths of each side, that is:
p = MN + NP + PQ + QR + RMp=MN+NP+PQ+QR+RM (1)
p = \sqrt{\overrightarrow{MN}\,\bullet \, \overrightarrow{MN}} + \sqrt{\overrightarrow{NP}\,\bullet \, \overrightarrow{NP}} + \sqrt{\overrightarrow{PQ}\,\bullet \, \overrightarrow{PQ}} + \sqrt{\overrightarrow{QR}\,\bullet \, \overrightarrow{QR}} + \sqrt{\overrightarrow{RM}\,\bullet \, \overrightarrow{RM}}p=
MN
∙
MN
+
NP
∙
NP
+
PQ
∙
PQ
+
QR
∙
QR
+
RM
∙
RM
(1b)
If we know that M(x,y) = (2,4)M(x,y)=(2,4) , N(x,y) = (5,8)N(x,y)=(5,8) , P(x,y) = (8,4)P(x,y)=(8,4) , Q(x,y) = (8,1)Q(x,y)=(8,1) and R(x,y) = (2,1)R(x,y)=(2,1) , then the perimeter of the pentagon MNPQR is:
p =\sqrt{(5-2)^{2}+(8-4)^{2}} + \sqrt{(8-5)^{2}+(4-8)^{2}}+\sqrt{(8-8)^{2}+(1-4)^{2}}+\sqrt{(2-8)^{2}+(1-1)^{2}}+\sqrt{(2-2)^{2}+(4-1)^{2}}p=
(5−2)
2
+(8−4)
2
+
(8−5)
2
+(4−8)
2
+
(8−8)
2
+(1−4)
2
+
(2−8)
2
+(1−1)
2
+
(2−2)
2
+(4−1)
2
p = \sqrt{3^{2}+4^{2}} + \sqrt{3^{2}+(-4)^{2}}+\sqrt{0^{2}+(-3)^{2}}+\sqrt{(-6)^{2}+0^{2}}+\sqrt{0^{2}+3^{2}}p=
3
2
+4
2
+
3
2
+(−4)
2
+
0
2
+(−3)
2
+
(−6)
2
+0
2
+
0
2
+3
2
p = 22p=22
The pentagon MNPQR has a perimeter of 22 units.
