The grade-point average in an econometrics examination was normally distributed with a mean of 75. In a sample of 10 percent of students it was found that the grade-point average was greater than 80. Can you tell what the s. d. of the grade-point average was?

To solve a standard deviation we require a specific result for each data. So this question(data from question) can not be enough to solve standard deviation.

b. an equilateral triangle inscribed in a circle

step-by-step explanation:

we are given the figure of two circles having a triangle inside.

now, we know that,

"when a figure is lying inside an another figure, then the outside figure is known as circumscribed figure and the figure lying inside is referred to as the inscribed figure".

as we see that, the circles are containing the triangle completely.

thus, the circles are the circumscribed figures and the triangle is the inscribed figure.

hence, we get, 'an equilateral triangle is inscribed in a circle'.

the answer is simply just 6n add the two together as they have an n