Answer:
32 (two significant figures)
Explanation:
We are given these two numbers written in scientific notations and we are to find their product, using the correct number of significant digits:
4.0 x 10^-2m and 8.1 x 10^2 m
Here, the exponents will cancel each other as one is negative and the other one is positive so we will be left with:
4.0 x 8.1 = 32.4
To two significant figures, it will be 32.