To find the surface area, you will use the formula area equals length times width to find the areas of all six shapes.
4×11, 4×5, and 11×5 are the three different areas shown. There are two of each, so 44×2, 20×2, and 55×2. 88+40+110=238 square mm.
238 square mm is the surface area.
10x+25 (expressions don't have equal signs)
51 + 3x+5 = 107
Simplify the left side:
3x + 56 = 107
Subtract 56 from both sides:
3x = 51
Divide both sides by 3:
x = 51 / 3
x = 17
Angle F and the outside angle of 107, need to equal 180 degrees.
F - 180 - 107 = 73 degrees.
