Question

Picture attached! HELP, will choose best response(:

Answer 1

It's either a right triangle or an acute triangle with an angle ridiculously close to 90 degrees. I would guess the correct answer is right triangle.

Answer 2

how did you find it out though?

Answer 3

Classify the triangle based on the side lengths 7, 15 and 21


right

acute

obtuse

no triangle can be formed with given sides

Answer 4

How would you do this one then?

Answer 5

I'm not sure if you're aware of the law of sine and cosine, so I will assume you don't.

One quick way to check the type of triangle:
Take the two smaller sides. If the sum of the two is less than or equal to the third length, then the three lengths can't make a triangle (the two smaller side lengths, even when they make a line, can't extend long enough to accommodate the third side).

\[\textrm{If the triangle can be formed, then take the two smaller sides and compare} \\ \textrm{the sum of the squares to the square of the third. In another form:} \\
\textrm{Compare: } a^2 + b^2 \textrm{ vs. } c^2. \\
\textrm{If the left hand side is equal to the right hand side, it's a right triangle.} \\
\textrm{If the left hand side is greater than the right hand side, it's an acute triangle.} \\
\textrm{If the left hand side is less than the right hand side, it's an obtuse triangle.}\]

Answer 6

alright thank you sooo much!