85 x 3 = 255
first 2 test grades were 81 and 86:
81 + 86 = 167

Need to find the 3rd to have exact average 85:
255 - 167 = 88

So her 3rd test needs to make 88 to make average of 85

Double check: 81 + 86 + 88 = 255 = 85 + 85 + 85

3 0

3 years ago

What is the exact solution of cos (17pi/6)?

kolbaska11 [484]

<span>The exact solution of cos (17</span>π<span>/6) is as follows:

First change the angle into degrees.

17(</span>π/6) (180°/π) = 510°

Then we calculate the cosine of the angle above and it as follows:

cos 510° = -(√3)/2

Hope this answers the question. Have a nice day.

4 0

2 years ago

Explain how can you use a quick picture to find 3 x 2.7

weeeeeb [17]

2.7
×3
=8.1
i tride my best

6 0

3 years ago

Read 2 more answers

Use distributive property to simplify (m-5)4

Blababa [14]

Answer:

4m-20