(a,b) =(5,5), (4,6),(3,7),(2,8),(1,9),(6,4),(7,3),(8,2),(9,1)
Explanation:
Let's analyze. So perimeter of a rectangle is given by the formula:
P =2 ⋅ (a+b).
So,
2
⋅
(
a
+
b
)
= 20
And we are given that Area 21
c
m 2 ⇒
a
⋅
b < 21
Back to perimter
2
⋅(
a
+
b
) =
20 ⇒ a
+
b =
20 2 = 10
And we are given a
⋅
b < 21
, which gives us pairs (
a
,
b
) =
(
5
,
5
)
,
(
4
,
6
)
,
(
3,
7
)
,
(
2
,
8
)
,
(
1,
9
)
,
(
6
,
4
)
,
(
7
,3
)
,(
8
,
2
)
,
9
,
1
)
