53 terms

# Geometry Terms Sem2

integrated geometry terms from second semester ½ap = ½ apothem*perimeter Theorems: 6.1: opposite sides of parallelograms are congruent 6.2: opposite angles of a parallelogram are congruent 6.3: diagonals of a parallelogram bisect eachother 6.9: each diagonal of a rhombus bisects two angles of the rhombus 6.10: the diagonals of a rhombus are perpendicular 6.11:the diagonals of a rectangle are congruent 6.15: the base angles of an isos. trap. are congruent 6.16: the diagonals of an isos. trap. are…
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Parallelogram
a quadrilateral with both pairs of opposite sides parallel
Rhombus
a parallelogram with four congruent sides
Rectangle
a parallelogram with four right angles
Square
a parallelogram with four congruent sides and four right angles
Kite
a quadrilateral with two pairs of adjacent sides congruent and no opposite sides congruent
trapezoid
a quadrilateral with exactly one pair of parallel sides
isoscles trapezoid
a trapezoid whose nonparallel sides are congruent
consecutive angles
angles of a polygon that share a side
base angles of a trapezoid
two angles that share a base of a trapezoid (congruent in isos. trap.)
midsegment of a trapezoid
the segment that joins the midpoints of the nonparallel opposite sides of a trapezoid
trapezoid midsegment theorem
1) the midsegment of a trapezoid is parallel to the bases 2) the length of the midsegment of a trapezoid is the average of the bases
base of a parallelogram
any side of the parallelogram
altitude
a segment perpendicular to the line containing that base drawn from the side opposite the base
height
length of altitude
area of a rectangle or parallelogram
b*h
area of a triangle
½(b*h)
pythagorean theorem
the sum of the squares of the lengths of the legs is equal to the square of the length of the hypotenuse
pythagorean triple
a set of nonzero whole numbers a, b, and c that satisfy the pythagorean theorem
a²+b²=c²
right triangle
a²+b²>c²
acute triangle
a²+b²<c²
obtuse triangle
45-45-90 triangle theorem
hypotenuse = √2*leg
30-60-90 triangle theorem
hypotenuse = 2short leg; long leg = √33*short leg
height of a trapezoid
the perpendicular distance between the bases
area of a trapezoid
½h(b1*b2)
are of a rhombus or kite
½d1*d2
distance from the center to any given vertex
apothem
perpendicular distance from the center to any given side
area of a regular polygon
½ap
circle
set of points all equidistant from a given point called center
segment with one endpoint on circle and other on center
congruent circles
diameter
segment with both endpoints on circle passing through center
central angle
an angle whose vertex is the center of the circle
semicircle
half a circle
minor arc
an arc smaller than a semicircle
major arc
an arc larger than a semicircle
arcs of the same circle that have exactly one point in common
mABC=mAB+mBC
circumference
distance around a circle; πd or 2πr
pi (π)
ratio of the circumference of a circle to it's diameter
concentric circles
circles on same plane with same centers
arc length theorem
length of AB = mAB/360*2πr
congruent arcs
arcs that have the same measure and are in the same circle or in congruent circles
sector of a circle
region bound by an arc of the circle and the two radii to the arc's endpoints
segment of a circle
region bound by an arc and the segment joining its endpoints
area of a circle
πr²
area of a sector of a circle
area of sector AOB = mAB/360*πr²
proportion
a statement that two ratios are equal; a/b = c/d; a:b = c:d
extended proportion
a statement that three or more ratios are equal; a/b = c/d = e/f; a:b = c:d = e:f
cross-product property
multiplying both sides of a/b = c/d by bd
similar (~)
two figures that have the same shape but no necessarily the same size
similarity ratio
the ratio of lengths of corresponding sides