The given triangle is an equilateral triangle. All the sides of an equilateral triangle are same. All interior angles are equal with measure 60 degree.

The distance from the center of an equilateral triangle to the midpoint of a side is known as apothem. In the given figure letter a represents the apothem.

Point D is the midpoint of BC,

$b=\frac{BC}{2}=\frac{8.7}{2}=4.35$

Use Pythagorean theorem in triangle COD. So, option 1 is correct.

$OC^2=OD^2+DC^2$

$5^2=a^2+(4.35)^2$

$25=a^2+18.9225$

$a=\pm 2.46526$

$a\approx\pm 2.5$

The distance can not be negative, so the length of the apothem is approximately 2.5 cm. Option 4 is correct.

The line OC bisects the angle C.

$tan(30^{\circ})=\frac{a}{b}$

$\frac{1}{\sqrt{3}=\frac{a}{4.35}$

$a\approx\pm 2.5$

Therefore option 2 is correct.

The perimeter of an equality triangle is

$P=3a=3(8.7)=26.1$

Option 3 is incorrect.

$A=\frac{\sqrt{3}}{4}a^2=\frac{\sqrt{3}}{4}(8.7)^2=32.77$

Option 5 is incorrect.

Therefore options 1, 2 and 4 are correct.

3 0

3 years ago

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Need help solving please

zzz [600]

Answer:

Step-by-step explanation:

because u have to single out the 3 x by subtracting 2 on both sides

8 0

3 years ago

Elvira’s cafeteria has cartons of milk that are typical of school lunch. The milk supplier charges $0.35 per carton of milk, in

FromTheMoon [43]

Write the equation out: (total cost: 0.35C[per carton] + 75[delivery charge]) ≤ 500. Subtract 75 on both sides and it would be: 0.35C ≤ 425. Divide 0.35 on both sides and you'll get C ≤ 1214. Therefore, the maximum # of cartons that Elvira can buy is 1214 cartons of milk.

3 0

3 years ago

The reciprocal of 18 is. The reciprocal of is 2/3 is

Leno4ka [110]

Answer:

1/18

3/2

Step-by-step explanation:

18 = 18/1 if the reciprocal means to flip the denominator and the numerator then just witched them so it would be 1/18

2/3 would be 3/2

4 0

3 years ago