Do you know how to do this question

Percentage of the area shaded = 55%

Solution:

Perimeter of the square = 40 cm

Each side of the square = = 10 cm

Area of the square =

                               = 10²

                               = 100

Total area of the square = 100 cm²

The unshaded portion is two triangles.

Base of the smaller triangle = 10 cm – 7 cm = 3 cm

Height of the smaller triangle = 10 cm

Area of the smaller triangle =

Area of the smaller triangle = 15 cm²

Base of the larger triangle = 10 cm – 4 cm = 6 cm

Height of the larger triangle = 10 cm

Area of the larger triangle =

Area of the larger triangle = 30 cm²

Area of the shaded portion = Area of the square – Area of the smaller

                                                   triangle – Area of the larger triangle

                                              = 100 cm² – 15 cm² – 30 cm²

Area of the shaded portion = 55 cm²

Percentage of the area shaded =

Percentage of the area shaded = 55%

the diameter is 16 cm. are you a teacher?

step-by-step explanation:

you didn't post any answer choices, so its not 100% clear what your teacher is looking for

however, log(15/7) is equivalent to log(15) - log(7)

i'm using the rule log(x/y) = log(x) - log(y)