L1-14 Review

Write the equation of a circle with center (7, 0) with radius 3.

• (x - 7)² + y² = 9

• x² + (y -7)² = 9

• (x - 7)² + y² = 3

• x² + (y -7)² = 3

Answer explanation

The standard form of a circle is (x-h)^2 + (y-k)^2 = r^2.

Where (h,k) is the center and r is the radius.

So we have a center (7,0) we plug it into the equation (x-7)^2 + (y-0)^2. Now we have a radius of 3. We subsitute that into r and 3^2 is 9

What are the coordinates of the center and the radius of the circle with equation (x - 4)² + (y - 3)² = 25 ?

• Center (4, 3)

  Radius = 5 units

• Center (4, 3)

  Radius = 25 units

• Center (-4, -3)

  Radius = 25 units

• Center (-4, -3)

  Radius = 5 units

Answer explanation

The standard form of a circle is (x-h)^2 + (y-k)^2 = r^2.

Where (h,k) is the center and r is the radius.

What we have to remember is that (x-h) reads as x oposite h. So when we take (h,k) out of the equation we have to remember that it is the opposite.

What is the center of the circle with equation x² + y² = 1?

• (1, 1)

• (0, 0)

• not enough information

Answer explanation

Since there is no numbers for the (h,k) values then it is (0,0). THe center of the circle is at (0,0)

Answer explanation

Answer explanation

Is the point (-3 , 5) inside, outside or on the circle with equation (x+2)² + (y-4)² = 9?

• Inside the Circle

• Outside the Circle

• On the Circle

Answer explanation

What best describes how the yellow triangle is translated to end up where the red triangle is?

How is trapezoid ABCD translated to trapezoid A'B'C'D'?

The focus is always inside the parabola.

• true
• false

A parabola is the set of all points equidistant from the focus and the directrix.

• true
• false