Question

Solve the triangle. Round lengths to the nearest tenth and angle measures to the nearest degree. a = 7, b = 7, c = 5

Answer 1

B. A = 69°, B = 69°, C = 42°??

Answer 2

sounds good.

Answer 3

wrong

Answer 4

Try Using cosine law

Answer 5

\[7^{2} = 7^{2} + 5^{2} - 2(7)(5)cosA\]

Answer 6

my answers need to be in degrees

Answer 7

you get \[cosA = \frac{ -25 }{ -70 }\] than do arc cosine. you get angle 69.07

Answer 8

i need degrees for a b n c ??

Answer 9

you get angles 41.8 and 69.07. again

Answer 10

A. A = 70°, B = 70°, C = 40°

B. A = 69°, B = 69°, C = 42°

C. A = 42°, B = 69°, C = 69°

D. A = 69°, B = 42°, C = 69°

Answer 11

?

Answer 12

Try D.

Answer 13

have to go.

Answer 14

thanks

Answer 15

deff not 69 deg

Answer 16

Note that the triangle is isosceles:

Answer 17

ok ? still confused

Answer 18

Now use the cosine law:\[\bf a^2=b^2+c^2-2bc \cos(A) \implies 5^2=7^2+7^2-2(7)(7)\cos(A)\]Note that 'A' is the angle opposite side BC. Now re-arrange and solve for cos(A):\[\bf \implies \cos(A)=\frac{-73}{-98}=0.7445 \implies \cos^{-1}(0.7445)=A=41.884 \ degrees\]

Answer 19

Now because the triangle is isosceles, the remaining two angles B and C are equal so we can find each of them by subtracting A from 180 and dividing the result by 2:\[\bf \angle B=\angle C=\frac{ 180 -41.884}{ 2 }=69.058 degrees\]Rounding off our results to the nearest degree we get:\[\bf \angle A =42 \ degrees\]\[\bf \angle B=\angle C=69 \ degrees\]

@britbrat4290

Answer 20

@britbrat4290 So your answer is correct =]