Question

Suppose an isosceles triangle ABC has A pi/4 = and b = 4 = c. What is the length of a^2?

a. 4^2(2-sqrt2)
b. 4^2 sqrt2
c. 4^2(2+sqrt2)
d. 4^2(sqrt2-2)

Answer 1

do you know the law of cosine ?

Answer 2

no

Answer 3

\[a ^{2} = b^{2} + c^{2} - 2bc \cos \alpha \]

Answer 4

so you have to apply this formula to calculate a^2

Answer 5

when it says and b=4=c does that mean c also equals 4?

Answer 6

yes

Answer 7

so it would be \[a^2=4^2+4^2-2(4)(4)\cos a\]

Answer 8

is the last a my (pi/4)?

Answer 9

yes,
and it is cos(pi/4)

Answer 10

yes it is

Answer 11

i got 9.37

Answer 12

i don't think you have to calculate the exact value, your answer must be on of the choices given

Answer 13

so its a

Answer 14

correct