In an all boys school, the height of the student body are normally distributed with a mean of 69 inches and a standard deviation of 5 inches. using the empirical rule, what percentage of the boys are between 54 and 84 inches tall?

99.7% of the boys are between 54 and 84 inches tall.

Step-by-step explanation:

The heights 54 and 84 inches are 3 standard deviations away from the mean. Thus, 99.7% of the boys are between 54 and 84 inches tall.

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'.

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40