all of these are applications of the distance formula
remember a^2+b^2=c^2
so the distance (c) is

a and b are legnths of legs so we find the legnths
the distance between points (x1,y1) and (x2,y2) is
D=

input points and find distance
1. (3,5) ot (7,3)
D=

=√(16+4)=√20=4.47
answer is A
2. (-3,-2) to (4,6)
D=

=√(49+64)=√113=10.63
answer is 10.6 units
3. from (1,7) to (9,-2)
D=

=√(64+81)=√145=12.04
answer is B
4. (-1,-2) to (6,2)
D=

=√(49+16)=√65=8.06
round
8.1 units
5. apply multipule times
A=(2,2)
B=(12,2)
C=(9,8)
D=(2,8)
find the distance between
A to B
B to C
C to D
D to A
we can see the distances between AB, CD and AD easily
just since 1 variable doesn't change, we just find the change in the other variable
AB=10 units
CD=7 units
DA=6 units
now
CB is from (12,2) to (9,8)
D=

=√(9+36)=√45=6.7
add everybody
AB+BC+CD+DA=10+6.7+7+6=29.7
we see that they put a trick and see option D, the not careful people will chose that but the quesiton askes for the perimiter
answer is B