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Gre Math Alg, Geom
part I. Formulas & methods for Triangles, Proportions, Geometry,
Question | Answer |
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How do you solve two simultaneous equations? find x 2x+ 5y= 20; 6x-1/2y=29 | alter to create problem that will result in isolation of desired variable. then compute; (10)6x-1/2y=29 60x-5y=290 2x + 5y = 20 62x=310 |
the measure of degrees along a straight line is how many degrees? | a straight line measures 180deg. |
the sum of all angles formed when 2 lines intersect = how many degrees? | >The sum of all angles when two lines intersect = 360. >opposite angles are equal to eachother |
what angle is formed by two perpendicular lines? | two perpendicular lines form a right angle |
what kind of triangle has three angles of 60 degrees? | an equal lateral triangle has three angles of 60 degrees. |
how do you make a right angle out of an equal lateral triangle? | draw line through the middle |
What kind of triangle is characterized by having two equal sides, and thus two equal angles? | an Isosceles triangle has two equal sides and the angles of those two sides are equal. |
> A of triangle = >>how does this relate to calculating the area of a quadrilateral? | > A of Triangle = 1/2 x BH >> this realates to the A of a square by the fact that we only measure 1/2 the base, if we took BH we would get the A of a quadrilateral, which is 2x any given triangle |
a 3-4-5 Triangle is characterized by what? | 3-4-5 Triangle is proportional to a given common multiple. thus: short side = 3, long side = 4, Hypoteneuse = 5 the actual length in any unit is not the key, only the proportion of the sides in relation to eachother. |
if a triangle has the following measurements: s1=15, s2=20, s3=25 what type of triangle is it? | a triangle with the measurements of 15, 20, 25 is a 3-4-5 Triangle. (3x5)=15,(4x5)=20,(5x5)=25 |
a 5-12-13 Triangle is characterized by what? | a ratio of (5x)(12x)(13x) |
If you have a trangle w/ s1=10, s2= 24, Hypoteneuse=? What kind of trangle is this? | A Triangle has s1=10, s2=24; the Hypoteneuse= 26 is a 5-12-13 Triangle |
x: x^sq rt (3): 2x = what kind of Triangle proportions? | x : x^sq rt (3) : 2x = 30:60:90 degree triangle |
if we have a triangle who's side lengths are in the ratio of; 1: 1: (square root of 2)... a) What kind of Triangle do we have? b) What are the internal angles? | In a triangle where the ratio of the sides are; 1:1: (sq rt 2);... a) This is an Isosceles triangle b) the angles are 45-45-90 |
What are the measurements of the internal angles of an Isosceles Triangle? | The internal angles of an Isosceles Triangle are 45-45-90 degrees |
A triangle who's side lengths are s1=5, Hypoteneuse=10,... a) What is the L of s2? b,c) What kind of Triangle do we have? What kind of Triangle is it? b) What are the internal angles? | Where there is a triangle w/ s1=5, Hypoteneuse=10 a) s2= 5^sq rt (3) b,c) The degree measurements of s1=30, s2= 60, Hypoteneuse=90 Thus, it is a 30-60-90 degree Triangle |
Pythagoeran Theorem: > Formula, Application, Limitations | Pythagoeran Theorem: a^2+b^2=c^2 >When you have 2 sides of a RIGHT Triangle, use to find Hypoteneuse |
If you divide a Right Triangle in a way which creates two smaller Right Triangles, >What is the characteristic of the resulting two Triangles in relation to the origional? | If you divide a Right Triangle in a way which creates two smaller right triangles,: >the resulting sides of the small triangles are proportional to the sides of the origional |
Circumference of a Circle =.... | Circumference of a Circle = 2 (phi) (r) |
Area of Circle =..... | Area of Circle = (Phi) 2r |
# of degrees in an angle formed by two radii at the center of a circle= ? (in relation to arc formed by their rotation) | the # of degrees in an angle formed by two radii at the center of a circle= the measure of degrees of the Arc formed by the two radii. |
What is a Trapezoid characterized by? How do you calculate its' Area? | A Trapezoid is: > a quadrilateral w/ four sides of different length > Area of Trapezoid = 1/2 (sum of all bases) x (Height) |
calculate Interest | Interest (I)= principal x interest rate x time |
Calculate distance traveled | d = rt distance= rate x time |
Calculate slope of a line (m).... | (Yb -Ya)/(Xb-Xa)= m |
Slope Intercept Form.. (m)=slope (b)= y-Intercept | y= m(x)+b OR y= b+m(x) |
Calculate midpoint on a line... (X point, y point) | X point: {(Xa+Xb)/2}, y point: {(Ya + Yb)/2)} |
Formula for Sum of Polygon Interior Angles...(n=# of angles) | Sum of Interior angles of Polygon = 180(n-2) |
Degree measurement of a single Interior Angle of regular Polygon... n=# of sides | Deg. of Inter.Angle of Polygon = [180(n-2)/n] |
(A) of Parallelogram=.... | (A) Parallelogram = bh |
Rectangular Prism: >(V)... > Surface Area ... | For Rec. Prism; (V)= lwh (SA)= 2(lw) + 2(hw)+ 2(lh) |
For General Prisms: V =... SA =... | For General Prisms: V= (Area of Base x Height) SA= (Sum of the three faces) x 2 |
Right Circular Cylinder: V= SA= | V= Area of Base x Height SA = 2(A of Base)+ Circumference(h) |
cube Pyramid V= SA= | V= 1/3(BH) = 1/3 (A of(Base))x H SA= B + (1/2 (Perim. x Slant Height)) |
Sphere V= SA= | Sphere V= 4/3(Π)(r^3) SA= 4(Π)(r^2) |
How can you use the Pythagorean Theorem when you only have degrees not points on a Right Triangle? | A = Square Root of [(C ^2)-(B^2)] B= Square Root of [(C ^2)-(A^2)] |
For a Triangle who has two angles of 45 deg. >Find deg. 3rd angle... & > Find Ratio of sides ... | >angle 3 = 90 >Ratio of sides sides = 1,1, square root of (2) |
For a Triangle who has one angle of 30 deg, another of 90 deg.. >Find deg. 3rd angle & > Find Ratio of sides = | >Angle 3 = 60 deg. >Ratio of sides is: (x): (sq.rt. of 3):(2x) |
if we have a right triangle with 2 sides 2 & 4.. > what is the other side & what is the Triangle ratio? > what degree ratio is the triangle? | in a triangle where to side are 2, & 4,... >the final side = 2(sq.rt (3) >triangle is a 30:60:90 deg. tri. |
Length of Arc= | L of Arch = (L/C) = (ABC(deg)/360) |
A of Arc= | A of Arc = Π(r^2) |