The equation of a circle:

(h, k) - a coordinates of the center
r - a radius

Answer:
the center: (3, -2)
the radius: 3
Use the compound interest formula.
A = P*(1 +r/n)^(n*t)
where P is the principal, r is the annual rate, n is the number of compoundings per year, and t is the number of years.
For the first investment, ...
A = 208,000*(1 +.08/4)^(4*5) = 309,077.06
For the second investment, ...
A = 218,000*(1 +.07/2)^(2*4) = 287,064.37
Totaling both investments at maturity, Megan has $596,141.43.
Pythagoras Theorem:
hipotenuse²=leg₁²+leg₂²
First posible triangle:
hypotenuse=13 (13²=169)
leg₁=12 ( 12²=144)
leg₂=5 (5²=25)
13³=144 + 25
Answer:can be side lengths of a triangle
Second triangle:
hypotenuse=12.6 (12.6²=158.76)
leg₁=6.7 ( 6.7²=44.89)
leg₂=6.5 (6.5²=42.25)
leg₁²+leg₂²=44.89+42.25=87.14≠158.76
Answer: cannot be side lenghts of a triangle.
third triangle:
hypotenuse=13 (13²=169)
leg₁=12 ( 12²=144)
leg₂=11 (11²=121)
leg₁²+leg₂²=144+121=265≠169
Answer: cannot be side lenghts of a triangle.
fourth triangle:
hypotenuse=13 (13²=169)
leg₁=6 ( 6²=36)
leg₂=4 (4²=16)
leg₁²+leg₁²=36+16=52≠169
Answer: cannot be side lenghts of a triangle.