Question

Help please,
Is the length x of the obtuse triangle in the diagram below to three significant figures is 5.43 cm.
(attached figure)

Answer 1

We can use a trig rule. Do you know which one?

Answer 2

No I'm not sure to be honest.

Answer 3

wouldn't you just use the Pythagorean theorem to solve for x? is it asking to prove that x = 5.43 cm?

Answer 4

It's asking if it's true or false

Answer 5

so then do a^2 + b^2 = c^2, solve for x and the value will tell you if it's true or false

Answer 6

so x^2 + 8.90^2 = 14.2^2
x^2 = 14.2^2 - 8.90^2
x^2 = 201.64 - 79.21
x^2 = 122.43
sqrt(x^2) = sqrt(122.43)
x = 11.064809081

Answer 7

ah ok thanks!

Answer 8

no prob!

Answer 9

you can't do Pythagorean because it's not a right angled triangle

Answer 10

then how would you solve it?

Answer 11

my bad. you would use the sine law to find the angle opposite the side 14.2, then find the third angle in the triangle using 180-angles, then use sine law to solve for x

Answer 12

did not see that it was an obtuse triangle

Answer 13

so then it's true?

Answer 14

you can also do the cosine law but sine law works fine

Answer 15

I got the answer to be true is that wrong?

Answer 16

I got two different solutions a=5.43 and a=22.53

Answer 17

how did you come across these solutions? and I'm assuming if you got the answer that is stated in the question, it should be true?