Question

Please help me out :)

Answer 1

Answer:

A  = 25√3 cm²

Step-by-step explanation:

View 5√3 cm as being the height of an equilateral triangle whose base is at the bottom of the purple figure.  To find the area of one such triangle, we use the area-of-a-triangle formula A = (1/2)(b)(h).  

                                                     opp

Using the sine function sin Ф = --------

                                                      hyp

we find the length of the hypotenuse, which is also the radius of the octagon, and because this is an equilateral triangle, is also the length of the base:

                √3       5√3 cm

sin 60° = -------- = ------------- , which produces the value of hyp:

                  2             hyp

                √3       5√3 cm

              -------- = ------------- , which produces the value of hyp:

                  2             hyp

√3·hyp = 10√3, or hyp = 10 cm

Then the area of this one triangle is A = (1/2)(b)(h), or

A = (1/2) (10 cm)(5√3 cm) = 25√3 cm²