What kind of triangle Is ACD
Obtuse triangle
isosceles triangle
right triangle
equilateral triangle

Option C:

Right triangle

Solution:

To find what kind of triangle is ΔACD.

Option A: Obtuse triangle

If any one of the angle in a triangle is more than 90°, then the triangle is obtuse triangle.

The angles in the given triangle ACD are not more than 90°.

So, the given triangle is not obtuse triangle.

Option B: Isosceles triangle

If any two sides of the triangle are equal, then the triangle is isosceles triangle.

The sides in the given triangle ACD are not equal.

So, the given triangle is not isosceles triangle.

Option C: Right triangle

If any one of the angle in a triangle is exactly 90°, then the triangle is right triangle.

In the ΔACD, angle A = 90°.

Therefore, ΔACD is right triangle.

Option D: Equilateral triangle

If all the three sides and all the three angles are equal, then the triangle is an equilateral triangle.

In ΔACD, not all the angles are equal.

Therefore , it is not an equilateral triangle.

Option C is the correct answer.

Hence ΔACD is a right triangle.

you can use a^2+ b^2=c^2