(05.01 LC)

Look at the figure shown below:

A triangle RPQ is shown. S is a point on side PQ and T is a point on side PR. Points S and T are joined using a straight line. The length of PS is equal to 28, the length of SQ is equal to 2x, the length of PT is equal to 35 and the length of TR is e

Rita is writing statements as shown to prove that if segment ST is parallel to segment RQ, then x = 24.

Statement Reason

1. Segment ST is parallel to segment QR Given

2. Angle QRT is congruent to angle STP Corresponding angles formed by parallel lines and their transversal are congruent

3. Angle SPT is congruent to angle QPR Reflexive property of angles

4. Triangle SPT is congruent to triangle QPR Angle-Angle Similarity Postulate

5. (2x + 28):95 = Corresponding sides of similar triangles are in proportion

Which of the following can she use to complete statement 5? (1 point)

28:95

28:35

60:95

60:35

28:35

Step-by-step explanation:

Since Rita is trying to prove that the two triangles are similar, she will be looking for corresponding sets of sides that have an equivalent ratio. Therefore, since for the big triangle she uses sides PQ and PR, the corresponding sides on the smaller triangle would be PS and PT, which have a ratio of 28:35. Hope this helps!

answer: learning objective(s)

·         describe the creation and use of systems of equations.

·         graph a system of linear equations on the coordinate plane and identify its solution.

introduction

sometimes graphing a single linear equation is all it takes to solve a mathematical problem. other times, one line just doesn’t do it, and a second equation is needed to model the situation. this is often the case when a problem involves two variables. solving these kinds of problems requires working with a system of equations, which is a set of two or more equations containing the same unknowns.

let’s take a look at systems of equations, and see what the graphs of individual equations within a system reveal about the mathematical relationship of the variables.

systems of equations

a system of equations contains two or more linear equations that share two or more unknowns. to find a solution for a system of equations, we must find a value (or range of values) that is true for all equations in the system.

the graphs of equations within a system can tell us how many solutions exist for that system. look at the images below. each show two lines that make up a system of equations (in the graph on the right the two lines are superimposed and look like a single line). how many points in common does each system of lines reveal?

one solution

no solutions

infinite solutions

if the graphs of the equations intersect, then there is one solution that is true for both equations.

if the graphs of the equations do not intersect (for example, if they are parallel), then there are no solutions that are true for both equations.

if the graphs of the equations are the same, then there are an infinite number of solutions that are true for both equations.

remember, the graph of a line represents every point that is a possible solution for the equation of that line. so when the graphs of two equations cross, the point of intersection lies on both lines, meaning that it is a possible solution for both equations. when the graphs of two equations never touch, there are no shared points and there are no possible solutions for the system. when the graphs of two equations lie on top of one another, they share all their points and every one is a possible solution.

graphing as a solution method

graphing equations in order to identify a specific point of intersection is usually not a precise way to solve systems because it is often difficult to see exactly where two lines intersect (unless you are using a computer-based graphing program that allows you to zoom in on a point). however, the graph of a system of equations can still give a good idea of what type of solution, if any, exists. let’s graph a system, and see how it works.

graph the system y = 3x and x + 2y = 4. how many solutions does this system have?

a graph of the two lines y = 3x and x + 2y = 4 shows us that the lines intersect, meaning that there is a single (x, y) value that satisfies both equations. looking at the graph does not tell us exactly where that point is, but we don’t need to know that information here, because the question only asks for the number of solutions.

so a system made of two intersecting lines has one solution. now let’s look at a different situation:

how many solutions exist for the system y -0.5x = 7 and 2y = x − 3?

plotting both equations, it looks like there is no solution—the lines are parallel. to check this finding, we can compare the slopes of the equations. to make that easy, we’ll rearrange the equations into slope-intercept form, or y = mx + b.   that gives us the equations y = 0.5x + 7 and y = 0.5x − 1.5.   yes, the slope of both lines is 0.5, which means the lines really are parallel. they never intersect, so there is no point that lies on both lines, and no solution to the system.

step-by-step explanation:

answer: 270

step-by-step explanation:

you have to times 200 by 1.35 to get your answer