Find the measure of Angle B A. 50° B. 55° C. 60° D. 65°
1 answer:
Option B. 55° is the correct answer
Step-by-step explanation:
"The sum of interior angles of a triangle is always 180°"
Given
m∠A=(3x+1)°
m∠B=(2x-1)°
m∠C = 40°
We know that
m∠A+m∠B+m∠C=180°
Putting the values of angles
Subtracting 40 from both sides
Dividing both sides by 5
We have to find Angle B,
So
m∠B = 2x-1 = 2(28)-1 = 56-1 = 55°
Hence,
m∠B=55°
Option B. 55° is the correct answer
Keywords: Triangle, Interior angles
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Answer:
solution given;
let
AB=a
AC=b=30ft
AB=c=20ft
<A=115°
By using Cosine rule.
a²=b²+c²-2bc cos angle
a²=30²+20²-2*30*20 Cos 115°
a²=1807.1419
a=√[1807.1419]
a=42.51
Side A is 42.51ft.
Again
Cos B=
Cos B=
Cos B=0.7687
<B=Cos -¹(0.7687)
<B=39.46°
Angle B is 39.46