how much of a radioactive substance must be presented to decay to 70 grams in 15 years if the half-life of the substance is 3.3 years
between 1300 and 1400 grams

F) 4√3

Step-by-step explanation:

The altitude of the triangle creates a right triangle.  The right triangle has a leg of 4 and a hypotenuse of 8.  Using the Pythagorean theorem,

a²+4² = 8²

a²+16 = 64

Subtract 16 from each side:

a²+16-16 = 64-16

a² = 48

Take the square root of each side:

√(a²) = √(48)

a = √(16*3)

a = 4√3