SOLUTION: The sides of a triangle are 3 cm, 5 cm and 7 cm respectively. Show that the largest angle is 120 degree, and find the area of the triangle.

SOLUTION: The sides of a triangle are 3 cm, 5 cm and 7 cm respectively. Show that the largest angle is 120 degree, and find the area of the triangle.

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Question 1076294: The sides of a triangle are 3 cm, 5 cm and 7 cm respectively. Show that the largest angle is 120 degree, and find the area of the triangle.
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
Using the law of cosines,

So,

.
.
.
To find the area, use Heron's formula,

So then,

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