If the sine of an acute angle is 3/5, what is the cosine of
that angle?

The cosine of the angle is 4/5.

Step-by-step explanation:

An acute angle is between 0º and 90º, in the first quadrant of the trigonometric circle, in which both the sine and the cosine are positive values.

For each angle , we have that:

We have that:

So

The cosine of the angle is 4/5.

56.6

step-by-step explanation:

the ratio of the perimeters is equal to the scale.

the ratio of the areas is equal to the square of the scale.

34 / 20 = k

a / 19.6 = k²

substituting:

a / 19.6 = (34 / 20)²

a = 19.6 (34 / 20)²

a ≈ 56.6

25/14 or 1.

step-by-step explanation:

the dots mean that it has infinitely more numbers behind it