McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles

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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?
McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles 1
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.
McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles 2
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.
McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles 3
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?
McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles 4
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.
McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles 5
Answer:
AB and CD are the two line segments from the connection points on the circle.

Question 6.
Identify the diameter.
McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles 6
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.
McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles 7
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.
McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles 8
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.
McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles 9
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.
McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles 10
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.
McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles 11
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.
McGraw Hill Math Grade 6 Lesson 23.4 Answer Key Circles 12
Answer:
AB and PQ are the two chords that have been drawn in the figure above.

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