If two lines are perpendicular, then they form right angles. If two lines meet at 90 angles. then they are perpendicular. Two lines meet at a 90 angle. a
Conclusion: The lines are perpendicular and meet at a 90 angle.

b
Conclusion: The lines are parallel.

c
Conclusion: The lines form a right angle.

d
Conclusion: The lines meet at a 90 angle.

The lines are Parallel

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.