The diagram shows a circle and an equilateral triangle. One side of the equilateral triangle is a diameter of the circle. The circle has a circumference of 48cm. Work out the area of the triangle.

(3 S.F)

Step-by-step explanation:

Diameter of circle (D) = one side of the equilateral ∆

Circumference of the circle = πD = 48 cm

Thus:

πD = 48

Divide both sides by π

D = = 15.3 cm (approximated to nearest tenth)

Since all sides an equilateral ∆ are equal, therefore, and the diameter, D, of the circle given is the same as the length of one side of the ∆, therefore, all sides of the equilateral triangle would be 15.3 cm.

Recall that the area of a triangle can be found if we know lengths of the two sides of the ∆ and the measure of the included angle between both sides.

Since an equilateral ∆ has equal angles, each measuring 60°, then we already have all the information needed to calculate the area of the ∆.

Thus:

Length of the two sides = 15.3 cm and

15.3 cm

Included angle = 60°

Use the following formula:

Where,

a = 15.3 cm

b = 15.3 cm

C = 60°

Plug the values into the formula to find the area.

(3 S.F)

step-by-step explanation:

there is a formula i can give you:

it is r^2*n*sin(360/n) divided by 2 where r represents the "radius" and n is the number of sides.

plug them in:

(10sqrt(3))^2*6*sin(360/6) divided by 2

100*3*6*sin(60) divided by 2

900*sin(60)

900*sqrt(3)/2

450*sqrt(3)

approx is 779.4 cm^2