Could someone please help me? Thank you and explain the work because I don’t get this

multiplication is multiplication.   it might feel harder depending on what level of math you are in, but generally it will be the same old stuff, while implementing some new concepts and methods of solving work.

i think the answer is 90 hope this

we know that

1) the inscribed angle measures half of the arc it comprises.

so

m∠dgf= > expression

2) the opposite angles in an inscribed quadrilateral are supplementary angles

so

m∠dgf=

m∠dgf=°

substitute in the expression to find the value of arc ef

therefore

the answer is

the measure of the arc ef is