If in a triangle ABC, angle B= 60° and b : c = 5 : 42, then find angle A.
Answers
Answered by
0
Answer:
cosB=
2ca
c
2
+a
2
−b
2
2
1
=
2ca
c
2
+a
2
−b
2
⇒c
2
+a
2
=b
2
+ca
⇒c
2
+a
2
−2ac=b
2
+ac−2ac
⇒(c−a)
2
=b
2
−ac
and a
2
+b
2
+c
2
=2b
2
+ac
Answered by
0
Answer:
I think you type the wrong question.
If If the ratio is 5 : 2
than,
B = 60° , b : c = 5 : 2
:. C = (60÷5)×2
= 12 × 2
= 24°
:. angel A = 180° — ( 60 + 24 )°
= 180° — 84°
= 96°
_____________________________________________
or, If the ratio is 5 : 4
than,
B = 60° , b : c = 5 : 4
:. C = (60÷5)×4
= 12 × 4
= 48°
:. angel A = 180° — ( 60 + 48 )°
= 180° — 108°
= 72°
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