Transcript Finding the Measure of Clock Angles Methods

*
1.2 Measurement of Segments and Angles
* There are many ways to find the measure of
the angle formed by the hands of an analog
clock.
* You may use one of the methods shown or find
your own method (that can be justified
logically and mathematically)
*
1.
Determine the rate of the hour hand.
2.
Determine the rate of the minute hand.
*
3.
Convert the total time to minutes and
multiply by the hour rate.
4.
Multiply the number of minutes by the
minute rate.
5.
Find the measure of the clock angles by
taking the difference. Make sure this is the
minor angle formed.
*
1.
Long (minute) hand = 6°⁄min. Multiply
#minutes by 6.
2.
Short (hour) hand = #hours x 30° + “long”/12
because long had travels 12 times faster.
3.
Measure of clock angle equals the
difference. Remember to subtract from
360°, if not a minor angle.
*
* Each interval between numbers is 30°.
* Determine the number of “whole” intervals
between the hands.
* Calculate the number of degrees for any
fractional parts of intervals. The diagrams that
follow illustrate this process.
*
4:38
18º
60
°
=
89°
11º
4:38
=
89°
19º
90
°
18º
11:14
= 107°
7º
*
2
3
º
60
°
24º
10:24
=
168°
12º
150º
6
°
7:42
12°
9º
*
3
0
º
21º
=
21°
1:53
12º
= 98.5°
*
60
°
2
6
.
5
º
12:33 =181.5°
360 – 181.5 =
13.5º
178.5°
*
150º
18º
12º
1
6
.
5
º
150°
12:20