Practice questions available in McGraw Hill Math Grade 6 Answer Key PDF Lesson 23.4 Circles will engage students and is a great way of informal assessment.
McGraw-Hill Math Grade 6 Answer Key Lesson 23.4 Circles
Exercises
IDENTIFY
Question 1.
What is the radius of the circle, if the diameter is 11 cm?
Answer:
The diameter is a straight line that passes through the center of the circle. The radius is half of the diameter.
PG = 11 cm = d
d = 2r
r = d/2
d = 11/2 = 5.5 cm
So, the radius of the circle is 5.5 cm
Question 2.
Identify the chord in the figure below.
Answer:
A chord of a circle is a straight line segment whose endpoints both lie on a circular arc.
In the above figure, AB is the chord of the circle whereas OC is the radius.
Question 3.
Identify the 2 radii below.
Answer:
The radius is half of the diameter.
The radius is the distance from the origin.
OA and OB is the radii of the given circle.
Question 4.
What are the 5 chords formed by inscribing the pentagon inside of the circle?
Answer:
A chord of a circle is a straight line segment whose endpoints both lie on a circular arc.
AB, BC, CD, DE, and AE are the 5 chords formed by inscribing the pentagon inside of the circle
Question 5.
Describe the two line segments from the connected points on the circle.
Answer:
AB and CD are the two line segments from the connection points on the circle.
Question 6.
Identify the diameter.
Answer:
The diameter is a straight line that passes through the center of the circle.
CB is the diameter of the circle.
CALCULATE
Question 1.
Calculate the circumference of the circle below. Use 3.14 for π.
Answer:
The circumference of a circle is the perimeter of the circle.
r = 15 in.
We know that the formula for the circumference of the circle is 2πr
C = 2πr
C = 2 × 3.14 × 15
C = 94.24 in.
Question 2.
Calculate the area of the circle below. Use 3.14 for π.
Answer:
The area of a circle is π multiplied by the square of the radius.
A = πr²
A = 3.14 × 5 × 5 = 78.5 sq. cm
So, the area of the circle is 78.5 sq. cm
Question 3.
Calculate the area and circumference of the circle below. Use 3.14 for π.
Answer:
The area of a circle is π multiplied by the square of the radius.
A = πr²
r = 3 ft
A = 3.14 × 3 × 3 = 28.27 sq. ft
We know that the formula for the circumference of the circle is 2πr
C = 2πr
C = 2 × 3.14 × 3 = 18.85 ft
Question 4.
Calculate the area and circumference of the circle below. Use 3.14 for π.
Answer:
The area of a circle is π multiplied by the square of the radius.
A = πr²
d = 3 yd
r = 1.5
A = 3.14 × 1.5 × 1.5 = 7.07 sq. yd
We know that the formula for the circumference of the circle is 2πr
C = 2πr
C = 2 × 3.14 × 1.5 = 9.42 yards
Question 5.
Calculate the area and circumference of the circle below. Use 3.14 for π.
Answer:
The area of a circle is π multiplied by the square of the radius.
A = πr²
r = 9 in
A = 3.14 × 9 × 9 = 254.47 sq. in
We know that the formula for the circumference of the circle is 2πr
C = 2πr
C = 2 × 3.14 × 9 = 56.55 in.
Question 6.
Name the two chords that have been drawn in the figure below.
Answer:
AB and PQ are the two chords that have been drawn in the figure above.