Question

(G.5C, 1 pt) Determine which measuresments CANNOT be the three sides of a triangle. OA. 4 cm, 9 cm, 12 cm OB. 2 cm, 12 cm, 13 cm O C. 9 cm, 9 cm, 9 cm O D. 4 cm, 4cm, 9 cm

Answer 1

we can use the photo to check

replace on the equations and notice a strange data

A. a=4 b=9 c=12

`\begin{gathered} \cos A=(9^2+12^2-4^2)/(2*9*12) \\ \cos A=(209)/(216) \\ A=0.25 \\ \end{gathered}`
`\begin{gathered} \cos B=\frac{4^2+12^2-9^2^{}}{2*4*12} \\ \cos B=(79)/(96) \\ B=0.60 \end{gathered}`
`\begin{gathered} C=180-0.6-0.25 \\ C=179.15 \end{gathered}`

A is right

B.a=2 b=12 c=3

`\begin{gathered} \cos A=(12^2+3^2-2^2)/(2*12*3) \\ \cos A=(149)/(72) \\ A=\cos ^(-1)(2.069) \\ A=error \end{gathered}`

arccosine has no response for values ​​greater than 1

So, B es wrong