# Two angles of a triangle are 70° and 80° The vertices of the triangle are on a circle of radius 3.5cm construct the triangle.

### Asked by lijimoljayan | 12th Sep, 2021, 06:26: PM

Expert Answer:

###
This construction of triangle is made using the sine rule of Triangle as given below

where a , b and c are sides of triangle . A, B and C are angles as shown in figure. R is radius of circumcircle.
Angles of triangle are , A = 30^{o } , B = 70^{o} and C = 80^{o}
a = 2R sin(A) = 7 × sin(30) = 3.5 cm
b = 2R sin(B) = 7 × sin(70) = 6.6 cm
c = 2R sin(C) = 7 × sin(80) = 6.9 cm
To get the required triangle , we construct the triangle with sides 3.5 cm, 6.6 cm and 6.9 cm

^{o }, B = 70

^{o}and C = 80

^{o}

### Answered by Thiyagarajan K | 16th Sep, 2021, 10:50: PM

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