giving brainlest , please don’t joke around.

67.5 mm²

Step-by-step explanation:

Alright, we're going to make 3 different smaller shapes

Shape (triangle)

a=1/2(b)ha=1/2(5(3)= 7.5

Shape (skinny rectangle)

a=l·wa=2·9= 18

Shape (bigger rectangle)

a=l·wa=7·6= 42

Add them all together

42+18+7.5= 67.5

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.