Answer:
10
Step-by-step explanation:
4+5=9 and 1/2+1/2 =1 so 9+1=10
O think it is c subtracting 6 because adding and subtracting is the same so it’s either c or d
Answer:
A ≈ 2 ft²
Step-by-step explanation:
The area (A) of a triangle using Heron's formula is
A = 
where s is the semiperimeter and a, b , c the sides of the triangle.
s =
=
=
= 4.5
Then
A = 
= 
= 
≈ 1.9843...
= 2 ft² ( to the nearest square foot )
This is usually used as a proof that triangles have 180°. Look at the attached figures. If you cut off angle A, angle B and angle C and rotate them so that their vertices touch, you form a half-circle out of them (or a straight line). We know that half a circle is 1/2 of 360° or 180; therefore all 3 angles in a triangle must add up to 180°.