To find the angle of the ramp from the ground, we can use the cosine function. In a right triangle, the cosine of an angle is defined as the adjacent side (base) divided by the hypotenuse (ramp).
Let \( A \) be the angle we want to find, the adjacent side is the base which is 45 inches, and the hypotenuse is the slanted portion which is 48 inches.
The cosine of angle \( A \) is given by:
\[ \cos(A) = \frac{\text{adjacent}}{\text{hypotenuse}} = \frac{45}{48} \]
Now, we can calculate \( \cos(A) \):
\[ \cos(A) = \frac{45}{48} \approx 0.9375 \]
Next, to find \( A \), we take the inverse cosine (arccos):
\[ A = \cos^{-1}(0.9375) \]
Using a calculator or trigonometric table to find \( A \):
\[ A \approx 20.90^\circ \]
Rounding to the nearest degree gives us approximately \( 21^\circ \).
Since this is not one of the options available, the closest choice is:
20°.
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