A(n,s)=(ns^2)/(4tan(180/n)), n=number of sides, s=side length
A(8,4.6)=(8*4.6^2)/(4tan22.5)
A(8,4.6)=42.32/tan22.5 m (exact)
A(8, 4.6)≈102.17 m^2 (to nearest hundredth of a square meter)
Hi there!

We can solve for x knowing that the sum of interior angles in a triangle is 180°.
The square at the bottom indicates a right angle, or 90°. Therefore:
180 = 90 + x + (x + 10)
Combine like terms:
180 = 100 + 2x
Subtract 100 from both sides:
180 - 100 = 2x
80 = 2x
Divide both sides by 2:
x = 40.