Answer:
the largest angle of the field is 149⁰
Step-by-step explanation:
Given;
perimeter of the triangular filed, P = 120 m
length of two known sides, a and b = 21 m and 40 m respectively
The length of the third side is calculated as follows;
a + b + c = P
21 m + 40 m + c = 120 m
61 m + c = 120 m
c = 120 m - 61 m
c = 59 m
B
↓ ↓
↓ ↓
↓ ↓
A → → → → → → → → → → → C
Consider ABC as the triangular field;
Angle A is calculated by applying cosine rule;
Angle B is calculated as follows;
Angle C is calculated as follows;
Therefore, the largest angle of the field is 149⁰.