How do I know if it’s similar, congruent or neither?

These two triangles are congruent.

Step-by-step explanation:

You know this bc the markings on the drawing show that Angle B and Angle D are congruent. Also that AB is parallel to CD. This means that Angle BAC and Angle DCA are congruent by ALTERNATE INTERIOR ANGLES. Also, AC is congruent to itself. That makes the two triangles congruent by ANGLE-SIDE-ANGLE.

Now, you need to know that "congruent" triangles (and shapes in general) are the same size and shape. "Similar" triangles (shapes) are the same shape but not necessarily the same size.

center (1,3) with radius 6

step-by-step explanation:

we must complete the square to find the center and radius of the circle.

first make sure the x and y squared terms have 1 as their coefficients. we also make sure x and y terms together.

we now create space between the x and y terms with parenthesis.

we complete the square by taking the middle terms -2x and the -6y - divide each and square them.

we add the squares to both sides.

simplify.

and write the quadratics in factored form.

the center is (h,k) or (1,3). the radius is the square root of 36 which is 6.