Answer:

Step-by-step explanation:
Property used: <em>An exterior angle of a triangle is equal to the sum of the opposite interior angles.</em>

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.
Step-by-step explanation:
5.
angle STQ is the supplementary angle (together they are 180° below line MQ) to 2x + 8.
above ST we have a group of 3 angles that combine to 180° :
2x + 8
90°
71 - x
so, to get x first :
2x + 8 + 90 + 71 - x = 180
x + 169 = 180
x = 11
so, the angle MTS =
2x + 8 = 2×11 + 8 = 22 + 8 = 30°.
6.
therefore, the angle STQ is
180 - angle MTS = 180 - 30 = 150°.
The 400th term is 425.There are floor(√400) = 20 squares in the range 1..400, so the 400th term will be at least 420. There are floor(∛420) = 7 cubes in the range 1..400, so the 400th term may be as high as 427. However, there are
![\lfloor\sqrt[6]{427}\rfloor=2](https://tex.z-dn.net/?f=%5Clfloor%5Csqrt%5B6%5D%7B427%7D%5Crfloor%3D2)
numbers that are both squares and cubes. Consequently, the 400th term will be 427-2 =
425.
Answer:
109
Step-by-step explanation:
81-19 is 62. if you add 109 then you could do 109-19 is 90