y component of →a=100sin45∘=100√2
y component of →b=100sin135∘=100√2
y component of →c=100sin315∘=−100√2
Resultant of y component=100√2+100√2−100√2=100√2units
x component of →a=100cos45∘=100√2
x component of →b=100cos45∘=−100√2
x component of →c=100cos45∘=100√2
Resultant of x component=100√2−100√2+100√2=100√2units
Total resultant of x and y component=(100√2)2+(100√2)2=100
Now, tanD=y−component /x− component=1
D=tan−1(1)=45∘
So, the resultant is 100 unit and 45∘ with x−axis