Question

$\text{Which of the following is correct about}\text{the}△ABC?$

• A. Acute
• B. Scalene
• C. Equilateral
• D. Isosceles

Answer 1

Answer: (A), (C), (D)

Isosceles


$\text{Since AB = AC,}\Delta ABC\text{is isosceles}\text{and thus}\angle B=\angle C.$

$\text{By angle sum property,}\angle A+\angle B+\angle C={180}^{\circ }\angle A+{60}^{\circ }+{60}^{\circ }={180}^{\circ }\angle A={180}^{\circ }-{120}^{\circ }\angle A={60}^{\circ }$

$\therefore \angle A=\angle B=\angle C={60}^{\circ }$

$\text{Since all angles of the triangle}\text{are equal,}\Delta ABC\text{is an equilateral triangle.}$

$\text{Also, we can see that all angles are}\text{less than}{90}^{\circ }.\text{Therefore,}\Delta ABC\text{is an acute angled triangle.}$