1. Reviewing skills needed to succeed in Geometry.

2. Cross Product Property!! ad = bc Solve:

3. Isolate ratio with variable first by adding 8 to both sides. Cross multiply, or think of it as multiplying both sides by 4. Answer: k = 80

4. To isolate the variable,multiply both sides by the reciprocal of, which is. You get x =. Reduce your answer by dividing numberator and denominator by 3. Final answer: x =

5. Simplify means leave your expression is in simplest terms: no like terms remain May need to distribute or combine like terms DO NOT SOLVE. If there is no equal sign in the problem, you don’t solve!!! Don’t add an equal sign if its not there Simplify: 3(x-4) + 2x Answer: 5x - 12

6. 1.Simplify: (x+6)(x-2) 2. Factor: x 2 +4x -12

7. Parallel lines = same slope Perpendicular lines = opposite, reciprocal slope Vertical lines = undefined slope ( Equation written as x = a ) Horizontal lines = slope of 0 (Equation written as y = b) To find the slope between 2 given points on a line:

8. Slope Intercept: y = mx + b m= slope, b = y intercept Standard Form: Ax + By = C Point Slope Form: y – y 1 = m (x – x 1 ) m = slope, (x 1, y 1 ) = any point on the line

9. Need a point on the line and the slope of the line If given 2 points, find the slope first, then use either point Use algebra to move back and forth between forms of a line Example: Write the equation in slope intercept form of the line with a slope of -1 that passes through the point (4, 3). 1.Use the model y = mx +b and substitute 3 in for y, -1 in for m, and 4 in for x. 2.Solve for b. 3.Write equation using the slope(m) and the y-intercept (b) Answer: y = -1x +7

10. 1.Write in slope intercept form the equation of a line with slope 2 passing through (3,-3). Answer: y = 2x -9 2.Write the equation of the vertical line passing through (6, 2). Answer: x = 6

11. X – intercept : y coordinate= 0 Y- intercept : x coordinate = 0 Can graph using intercepts or in slope-intercept form To graph in slope-intercept: graph the y-intercept, use slope to graph other points Positive slope: rise to right Negative slope: fall to the right Graph the equation: y = -2x + 5

12. Difference of Two Perfect Squares: (a 2 -b 2 ) = (a-b)(a+b) Factor r 2 – 25 Answer: (r +5 )(r – 5)

13. Perimeter: The sum of the lengths of the sides of a polygon (called circumference for circles) Units of measurement: in, yds, ft, miles, meters, etc.. Area: The number of square units a polygon encloses Units of measurement: in 2, cm 2, mi 2, etc…

14. base length: b height: h Perimeter: 2b + 2h Area: bh Example: Find the perimeter and area of a rectangle with base 2 yd and height 5 ft. Answer: Perimeter = 14 ft; Area = 10 ft 2 b h

15. Radius: r Diameter: d =2r Circumference: C= d OR C= 2 r Area: A = r 2 d r

16. If directions say leave in terms of, THEN LEAVE THE IN YOUR ANSWER!!!! Otherwise, use button on calculator. EX. Find the circumference of a circle with a diameter of 4 ft to the nearest tenth. Find the area of the circle and leave in terms of.

17. Area = b h

18. Rectangular Prism: Surface Area = 2lw + 2 lh + 2 wh Volume: lwh

19. No perfect square factor left under the radical Use the following multiplication property of radicals: Table of perfect squares: Example: Simplify Find highest perfect square factor of 50. It is 25 ( 25 X 2 = 50) Rewrite the radical: Simplify: n12345678910 n2n2 149162536496481100 How did we get 5 ??? Square root of 25 is 5.

20. Sum of all angle measures in a triangle is always 180˚ Acute triangle: all angles less than 90˚ Obtuse triangle: one angle more than 90˚ Right triangle: one angle = 90˚ Pythagorean Theorem: used to find missing side lengths in a RIGHT triangle a 2 + b 2 = c 2 c has to be the hypotenuse (side opposite right angle)

21. Made up of 2 rays that intersect at a common point, called the vertex. Supplementary angles: add up to 180˚ Complimentary angles: add up to 90˚

22. Line n is the transversal Creates 8 angles: Pairs of angles formed are: 1.Same side interior ( 4 and 5) 2.Alternate interior ( 3 and 5) 3.Corresponding ( 2 and 6) 4.Same side exterior ( 2 and 7) 5.Alternate exterior ( 1 and 7)

23. Corresponding angles are congruent ( meaning of equal measure) Alternate interior angles are congruent Same side interior angles are supplementary Alternate exterior angles are congruent Same side exterior angles are supplementary