Bianca calculated the height of the equilateral triangle with side lengths of 10. tangent (30) = StartFraction 5 Over h EndFraction An equilateral triangle with side lengths of 10 is shown. A bisector is drawn to split the side into 2 equal parts and splits the angle into 2 30 degree segments.
Then, she used the formula for area of a triangle to approximate its area, as shown below.

A = one-half b h. = one-half (10) (8.7). = 43.5 units squared.

Calculate the area of the equilateral triangle using the formula for area of a regular polygon, and compare it to Bianca’s answer.

The apothem, rounded to the nearest tenth, is
units.

The perimeter of the equilateral triangle is
units.

Therefore, the area of the equilateral triangle is
, or approximately 43.5 units2.

The calculated areas are
.

In a test for esp (extrasensory perception), the experimenter looks at cards that are hidden from the subject. each card contains either a star, a circle, a wave, a cross or a square.(five shapes) as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. when the esp study described above discovers a subject whose performance appears to be better than guessing, the study continues at greater length. the experimenter looks at many cards bearing one of five shapes (star, square, circle, wave, and cross) in an order determined by random numbers. the subject cannot see the experimenter as he looks at each card in turn, in order to avoid any possible nonverbal clues. the answers of a subject who does not have esp should be independent observations, each with probability 1/5 of success. we record 1000 attempts. which of the following assumptions must be met in order to solve this problem? it's reasonable to assume normality 0.8(1000), 0.2(1000)%30 approximately normal 0.8(1000), 0.2(1000)% 10 approximately normal srs it is reasonable to assume the total number of cards is over 10,000 it is reasonable to assume the total number of cards is over 1000