The formula for a triangular pyramid is 1/3AH. A is the area of the base. H is the height of the pyramid. So to find the area of a right triangle, you would use the formula (a x b)/2. So (10 x18)/2 is 90 inches^2. Now you can fill in the first formula. 1/3(90 x 14), which equals 420 inches^3. I hope you find this helpful (if correct.)
Point-slope form is where y1 and x1 are your points from the coordinate and m is the slope. So yours would look like this: y-(-4)=-3(x-(-1)) or y + 4 = -3(x + 1)
where y1 and x1 are your points from the coordinate and m is the slope. So yours would look like this: y-(-4)=-3(x-(-1)) or y + 4 = -3(x + 1)