The angles of triangle are (x + 10)o, (2x - 40)o and (3x - 90)o. Which of the following accurately describes the triangle?
A
it is a scalene triangle
B
it is right angled isosceles triangle
C
t is an equilateral triangle
D
It is an isosceles triangle but not right angled
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
(x + 10)o + (2x - 40)o + (3x - 90)o = 180
6x - 120 = 180
6x = 180 + 120
6x = 300
x = \(\frac{300}{6}\)
x = 50
x + 10o = 50o + 10o = 60o
2x - 40 = 2(50o) - 40 = 60o
3x - 90 = 3(50o) - 90o = 60o
Hence, it is an equilateral triangle
Source: Myschool Past Questions Archive (Record #36474)