Answer:
x has a value of 71, making D the correct answer.
Step-by-step explanation:
Because this is an isosceles triangle, we know that the bottom two angles are equal. We also know that the sum of the angles inside a triangle will always come to 180°. With that in mind, we can simply subtract 38° from 180° and divide by two to get the correct answer.

So the correct answer is D, 71 degrees.
Use PEMDAS
P Parentheses first
E Exponents (ie Powers and Square Roots, etc.)
MD Multiplication and Division (left-to-right)
AS Addition and Subtraction (left-to-right)

Unknown side is 4km, perimeter is 12m, and area is 3.5m^2
Answer:
Surface Area: 310 square inches.
Step-by-step explanation:
There are two ways to do this:
A) Formula for Surface Area of a Rectangular Prism = 2 * ( l*w + w*h + h*l). Where l is length, w is width & h is height. Based on the question:
l = 10 inch
w = 5 inch
h = 7 inch
Surface Area = 2 * ( 10*5 + 5*7 + 7*10) = 310 square inches.
B) Formula for Area of Rectangle = l*w, where l is length & w is width.
Look at the picture, I have marked the corners O,P,Q,R,S,T,U,V,W,X,Y,Z
If we calculate the Area of each rectangle and add them all we will get the surface area automatically.
- Area of PQRS = 10*7 = 70 square inches
- Area of STUV = 7*5 = 35 square inches
- Area of VWXY = (7+5)*10 = 120 square inches
- Area of ORYZ = 7*5 = 35 square inches
- Area of RSVY = 10*5 = 50 square inches
Now add them all = 70+35+120+35+50 = 310 square inches.