9. What is the area of the region left if three equilateral triangles are cut off from a semi circle of radius 4cm? *

Step-by-step explanation:

For the equilateral triangle in a semicircle of radius 4cm.

Side Lengths =4cm

Angles =60 degrees

Therefore, the area of one equilateral triangle

Area of the three equilateral triangle

Area of the semicircle

Therefore, the area left over =Area of Semicircle -Area of Triangles

=25.1327-20.7846

=

c. y = 1/4 x + 5

step-by-step explanation:

first, put the equation of the line on the graph into slope-intercept form

(y = mx + b):   y = -4x + 8

second, a perpendicular line has to have "an opposite/reciprocal slope" to the original slope. so, find the "m" value in your original equation (it's -4, right? )

original slope: m = -4   perpendicular slope: change the sign to its opposite and find the reciprocal ("flip" the number)

new slope is now positive (b/c the original slope was negative 4), and it's 1/4 (not the original slope of 4 or 4/1)