Calculate the area of quadrilateral ABCD.
State the units of your answer.

158.76 cm²

Step-by-step explanation:

Quadrilateral ABCD is composed of 2 right triangles

Construct the line BD, then

Δ ABD and Δ BCD are the 2 right triangles.

The area (A) of a triangle is calculated using

A = bh ( b is the base and h the perpendicular height )

Δ ABD with b = 18 and h = 7.5

A = × 18 × 7.5 = 9 × 7.5 = 67.5 cm²

Δ BCD with b = 15.6 and h = 11.7

A = × 15.6 × 11.7 = 7.8 × 11.7 = 91.26 cm²

Thus

area of ABCD = 67.5 + 91.26 = 158.76 cm²

the first one is x^2+2x+2

the second one is x^2+4

the last one is x^2-4x+8

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.