Question

What is the measure of ∠T, rounded to the nearest degree?

Answer 1

cosine theorem
3²=5²+7²-2*5*7*cosT
9=25+49-70*cosT
9-74=-70 *cos T
-65/(-70)= cos T
T = arccos (65/70)≈22°

Answer 2

In this question, we use law of cosine which is

`RS^2 = RT^2 + ST^2 -2(RT)(ST) cos T`

Substituting the given values of RS,RT, ST , we will get

`image`

`cos T = (65)/(70)`

Taking inverse cosine on both sides

`T = cos^(-1) ( (65)/(70))`

`T = 22`