Area of Circle: 21 Century Mathletes Pp. 302 - 305 Melcs-Mg-Bow M5Me-Iva-74
Area of Circle: 21 Century Mathletes Pp. 302 - 305 Melcs-Mg-Bow M5Me-Iva-74
Area of Circle: 21 Century Mathletes Pp. 302 - 305 Melcs-Mg-Bow M5Me-Iva-74
Circle
21st Century MATHletes pp. 302 – 305
MELCs- MG-BOW M5ME-Iva-74
Game: What am I?
Directions: Using show-me board. Unscramble the
letter to name the following:
IUSRAD
• My constant
PI
value is 3.14.
IP
• I am the
distance
around the
circle.
CIRCUMFERENCE
CURCIMENCEREFE
• I am the number
of square units
covering a given
plane figure.
AERA AREA
GROUP ACTIVITY
Mechanics
1. Complete the circular puzzle.
2. Trace the given circular puzzle in the
graphing paper.
3. Shade the circle. Count and write the
number of shaded squares covering the
circle.
4. The first group who finish
will clap their hands three
times and shout the name of
the group (the name of the
group depends on the figure
they formed from the puzzle).
5. The winner will be given a
reward and a consolation to
the other group.
A street sweeper is
working on his area
when he noticed an open
manhole. For the safety
of the pedestrian, he
know that he must find a
cover for the manhole.
He found an old manhole
cover in their stock room
that has a top surface area
of 3000 square centimeter. If
the diameter of the open
manhole is 60centimeter,
would the old manhole
cover be useful?
1. What is asked in the
problem?
• Would the old manhole cover
be useful?
2. What are the given facts?
• 3000 sq. cm surface area of the
manhole cover,
• 60cm diameter of the open manhole
• and pi with a constant value of 3.14
3.What is the formula?
•A = πr2
4. Solve
A = πr2
r=d/2 r = 30cm
r2 = 30cm x 30cm
r2 = 900cm2
π = 3.14
A = 3.14 x 900cm2
A = 2826 cm2
Area of cover – area of manhole
3000 cm2 - 2826cm2
=174cm2
Would the old manhole cover be useful?
2.r=20cm A= cm 2
3.d=6cm A= cm 2
•What is the formula in
finding the area of a
circle?
A = πr 2
Complete the table.
Diameter Radius Area
(unit2)
Clock 20cm
Dish 9cm
Fish pond 8m
Quiz. Find the area of each circle.
4. d = 10m 5. d = 6m
Assignment.
A. Find the area of each circle with the given radius.
1. r = 32cm
2. r = 4.5ft
3. r = 4dm
B. Find the area of each circle with the given
diameter.
4. d = 12inches
5. d = 8feet