100% -30% = 70 x 100 x sales tax
Answer: 
Step-by-step explanation:
The perimeter of a rectangle can be calcualated with this formula:

Where "l" is the lenght and "h" is the height.
The area of a rectangle can be found with this formula:

Where "l" is the lenght and "h" is the height.
In this case we know that:

Therfore, we can susbsitute them into
and solve for "h" in order to find its value:

Find two number whose sum is 3 and whose product is -40. These are -5 and 8. Then, factorizing, we get:

The positive value is the height. Then:

Since the length is 3 centimeters greater than its height, we get that this is: Then:

Substituting values into
, we get that the perimeter is:

NOT NECESSARILY would a triangle be equilateral if one of its angles is 60 degrees. To be an equilateral triangle (a triangle in which all 3 sides have the same length), all 3 angles of the triangle would have to be 60°-angles; however, the triangle could be a 30°-60°-90° right triangle in which the side opposite the 30 degree angle is one-half as long as the hypotenuse, and the length of the side opposite the 60 degree angle is √3/2 as long as the hypotenuse. Another of possibly many examples would be a triangle with angles of 60°, 40°, and 80° which has opposite sides of lengths 2, 1.4845 (rounded to 4 decimal places), and 2.2743 (rounded to 4 decimal places), respectively, the last two of which were determined by using the Law of Sines: "In any triangle ABC, having sides of length a, b, and c, the following relationships are true: a/sin A = b/sin B = c/sin C."¹
Answer:A
Step-by-step explanation: