Unit 10 Review Area Formulas
FOR EACH FIGURE: IMAGINE the shape THINK of its AREA FORMULA
The “base” of the polygon does not need to be on the bottom!
! The HEIGHT of the polygon does not need to be vertical!
The base and height must be PERPENDICULAR to each other!
RECTANGLE
A = bh
The base and height must be perpendicular to each other. h b
PARALLELOGRAM
A = bh
The base and height must be perpendicular to each other. The height can be outside the figure. h b
SQUARE
A = s 2 A = bh
All 4 sides are congruent. A=bh becomes A=s 2 s s
TRIANGLE
A =
The base and height must be perpendicular. base b h
TRAPEZOID
A =
The bases are parallel. b 1 b 2 h
RHOMBUS
A =
Don’t add the diagonals. MULTIPLY the diagonals.
KITE
A =
Don’t add the diagonals. MULTIPLY the diagonals.
REGULAR POLYGON
A =
To find the central angle, divide 360 by the number of sides.
A = Apothem = a Perimeter = p a
Bonus: Triangle given SAS
A =
a Cb
Circle Area
A =
The radius is half of the diameter. r
CIRCUMFERENCE
C = C =
C = r
Quick Check:
Circle Area
A =
REGULAR POLYGON
A =
TRAPEZOID
A =
KITE
A =
SQUARE
A = s 2 A = bh
PARALLELOGRAM
A = bh
CIRCUMFERENCE
C = C =
RHOMBUS
A =
TRIANGLE
A =
RECTANGLE
A = bh
Triangle