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ClockGeometry
Half PastQuarter Past Quarter Till
How many hours does one
revolution of the minute
hand around the face of a
clock represent?
How many hours does one
revolution of the minute
hand around the face of a
clock represent?1
How many minutes does
one revolution of the minute hand around the face of a
clock represent?
How many minutes does
one revolution of the minute hand around the face of a
clock represent?60
If there are 12 numbers on a
clock, how many minutes are
there between 2 consecutive numbers?
If there are 12 numbers on a
clock, how many minutes are
there between 2 consecutive numbers?
60 ÷12=5
How many minutes are
there between the numbers
12 and 6?
How many minutes are
there between the numbers
12 and 6?5x6=30
30 is what
part of 60?
30 is what
part of 60? One half
How is another way to
express the time 12:30?
How is another way to
express the time 12:30?
Half past twelve
How many minutes are
there between the numbers
12 and 3?
How many minutes are
there between the numbers
12 and 3?5x3=15
15 is what
part of 60?
15 is what
part of 60?
One quarter
How is another way to
express the time 12:15?
How is another way to
express the time 12:15?
Quarter past twelve
How many minutes are
there between the numbers 9
and 12?
How many minutes are
there between the numbers 9
and 12?5x3=15
15 is what
part of 60?
15 is what
part of 60? One
quarter
How is another way to
express the time 12:45?
How is another way to
express the time 12:45? Quarter till
one
The Clock asA Geometric
Figure
What geometric
figure does the face of this
clock represent?
What geometric
figure does the face of this
clock represent? A circle
How many degrees are there in a
circle?
How many degrees are there in a
circle?
360°
How many minutes are there in one revolution of the minute
hand?
How many minutes are there in one revolution of the minute
hand? 60
If a clock can be seen as a circle, how
many degrees does each
minute represent?
If a clock can be seen as a circle, how
many degrees does each
minute represent?
360°÷60=6°
How many minutes are
there between the numbers 12 and 1 on a
clock?
How many minutes are
there between the numbers 12 and 1 on a
clock?5
How many degrees are
there between the numbers 12 and 1 on a
clock?
How many degrees are
there between the numbers 12 and 1 on a
clock? 6°x5=30°
How many minutes are
there between the numbers 12 and 3 on a
clock?
How many minutes are
there between the numbers 12 and 3 on a
clock? 15
How many degrees are
there between the numbers 12 and 3 on a
clock?
How many degrees are
there between the numbers 12 and 3 on a
clock? 6°x15=90°
If we draw a line from the center of the
clock to the number 12, another line from the number 12 to the number 3, and a third line from the number 3 back to the center of the clock, what
geometric figure do we have?
If we draw a line from the center of the
clock to the number 12, another line from the number 12 to the number 3, and a third line from the number 3 back to the center of the clock, what
geometric figure do we have?
A triangle
If there are 90° between the
number 12 and the number 3,
how many degrees are there in the angle at the
center of the circle?
If there are 90° between the
number 12 and the number 3,
how many degrees are there in the angle at the
center of the circle?
90°
Can this triangle be
called a right
triangle?
Can this triangle be
called a right
triangle?Yes, a right triangle is a
triangle with one 90° angle.
If the three angles of a triangle add up
to 180°, and the angle at the center of the circle is 90°, and the other two angles are equal,
how many degrees are in each?
If the three angles of a triangle add up
to 180°, and the angle at the center of the circle is 90°, and the other two angles are equal,
how many degrees are in each?
180°-90°= 90°90°÷2=45°
Is the distance between the center of a
circle and any point on its
circumference equal?
Is the distance between the center of a
circle and any point on its
circumference equal?
yes
Can this triangle be called an isosceles triangle?
Can this triangle be called an isosceles triangle?
Yes, an isosceles triangle is a triangle with two equal sides and
two equal angles.
How many degrees are
there between the numbers 5 and 7 on a
clock?
How many degrees are
there between the numbers 5 and 7 on a
clock?6°x10=60°
If we draw a line from the center of the clock
to the number 5, another line from the
number 5 to the number 7, and a third line from the number 7 back to the center of the clock, what
geometric figure do we have?
If we draw a line from the center of the clock
to the number 5, another line from the
number 5 to the number 7, and a third line from the number 7 back to the center of the clock, what
geometric figure do we have?
A triangle
If there are 60° between the
number 5 and the number 7, how
many degrees are there in the angle
at the center of the circle?
If there are 60° between the
number 5 and the number 7, how
many degrees are there in the angle
at the center of the circle? 60°
If the three angles of a triangle add up
to 180°, and the angle at the center of the circle is 60°, and the other two angles are equal,
how many degrees are in each?
If the three angles of a triangle add up
to 180°, and the angle at the center of the circle is 60°, and the other two angles are equal,
how many degrees are in each?
180°-60°= 120°120°÷2=60°
Can this triangle be called an
equilateral triangle?
Can this triangle be called an
equilateral triangle?
Yes, a triangle with three 60° angles is an equilateral triangle.
Review
1. An hour has 60 minutes.
2. 15 minutes make a quarter hour.
3. For 15 minutes after an hour we can say quarter past the hour.
4. For 45 minutes after an hour we can say quarter till the next hour.
5. For 30 minutes after an hour we can say half past the hour.
6. A circle has 360°.7. Each minute on
a clock represents 6° on the circumference of a circle.
8. A triangle has three sides.
9. A right triangle has one 90° angle.
10. An isosceles triangle has two equal sides and two equal angles.
11. An equilateral triangle has three equal sides and three 60° angles.
12. Geometry is everywhere. Just look for it!
Prepared by
Robert Janak
Beaumont,
Texas