Question

Find the largest angle of the triangle whose sides are 7 cm, 5 cm, and 3 cm

Answer 1

Answer:

120 degrees

Step-by-step explanation:

Using Cosine rule,

$7² = 5² + 3²- 2*5*3 *cosx$

Bringing like terms in same place

$49-25-9 = -30\cosx$

$cosx = -15/30 = -1/2$

The value of cos -1/2 is about 120 degrees

$x = 120 \ degrees$