Answer:
D
Step-by-step explanation:
Parallel lines have the same gradient.
A line with a slope of zero is a horizontal line. Although two lines that have a slope of zero will result in two parallel lines, not all parallel lines are horizontal lines. Since the question is asking for which statement <u>must</u> be true, option A is incorrect.
If the slopes of two lines are negative reciprocals, they are perpendicular to each other. This is because the product of the gradients of 2 perpendicular lines is -1. Let the gradient of the first line be A and the other be B.
AB= -1


Thus, option B is incorrect too.
Undefined slopes gives vertical lines. Like option A, if two lines have an undefined slope, they will be parallel to each other. However since parallel lines are nit necessarily vertical lines, option C is also incorrect.
On #29 x = 12 and <apb = 90° and <dcb = 40° and on #30 all I dont even understand, sorry
Answer:
When two lines are cut by a transversal, the pairs of angles on one side of the transversal and inside the two lines are called the consecutive interior angles . If two parallel lines are cut by a transversal, then the pairs of consecutive interior angles formed are supplementary
Step-by-step explanation: