Answer: 60
Step-by-step explanation:
Using Heron's formula, we know that
Step 1: Calculate "s" (half of the triangles perimeter):
s = (a+b+c)/2
Step 2: Then calculate the Area:
Herons formula A = sqrt( s(s-a)(s-b)(s-c) )
So S = 36/2 = 18
so 
So our final answer is the square root of 3600, which equals 60.
For number 11 the third angle would be equal X as the second angle is, since the two sides next to the those angles are congruent. Then you would have to set an equation saying that 2x + 38= 180 and then you can just solve for X
Answer:
<h2>SA = 5645cm²</h2>
Step-by-step explanation:
We have three pairs of congruent rectangles
9cm × 4m; 9cm × 5cm and 4m × 5cm
We know 1m = 100cm, therefore 4m = 400cm
The formula of an area of a rectangle l × w:
A = l · w
Substitute:
A₁ = 9cm · 4m = 9cm · 400cm = 3600cm²
A₂ = 9cm · 5cm = 45cm²
A₃ = 4m · 5cm = 400cm · 5cm = 2000cm²
Calculate the surface area:
SA = A₁ + A₂ + A₃
SA = 3600cm² + 45cm² + 2000cm² = 5645cm²
