Question

Find angle of an isosceles triangle if ratio of the base angle to the vertical angle is 2:5

Answer 1

in an isosceles triangle base angles are same
let A and B be the base angles(A=B) and C be the vertical angle given that B:C= 2:5
B/C=2/5
A=B=2/5C
and sum of angles of triangle is 180
A+B+C=180
2B+C=180 (A=B)
2×2/5C+C=180 (B=2/5C)
4/5C+C=180
9/5C=180
C=100
A=B=2/5×100
A=B=40
therefore angles of an isosceles triangle are 100, 40, 40

Answer 2

Let the 2 angles be 2x and 5x------------------------------------- In a triangle sum of triangle=180and let third angle be 180-(2x+5x)=180-(2x+2x)----(angles Opp to equal sides) Therefore 180=2x+5x+180-(2x+2x)------------------------ 180=7x+180-4x ......I am tired!! Sry idk