A building casts a shadow reaching 13 feet from the base of the building, with a diagonal distance of 15 feet from the top of the building. Using the inverse of sine, what is the approximate angle formed between the top of the building and the shadow? (1 point)

• 60°
• 90°
• 45°
• 30°

1 answer

To find the angle formed between the top of the building and the shadow, we can use trigonometry. The scenario involves a right triangle where:

  • The opposite side (height of the building) is unknown.
  • The adjacent side (length of the shadow) is 13 feet.
  • The hypotenuse (diagonal distance) is 15 feet.

To find the angle, we need to determine the height of the building using the Pythagorean theorem:

\[ c^2 = a^2 + b^2 \] Where:

  • \(c\) is the hypotenuse (15 feet),
  • \(a\) is the height of the building,
  • \(b\) is the shadow (13 feet).

Let's calculate the height (a):

\[ 15^2 = a^2 + 13^2 \] \[ 225 = a^2 + 169 \] \[ a^2 = 225 - 169 \] \[ a^2 = 56 \] \[ a = \sqrt{56} \approx 7.48 \text{ feet} \]

Now we can find the angle using the sine function:

\[ \sin(\theta) = \frac{\text{opposite}}{\text{hypotenuse}} = \frac{a}{c} = \frac{7.48}{15} \]

Calculating the sine:

\[ \sin(\theta) \approx \frac{7.48}{15} \approx 0.4987 \]

Now using the inverse sine function:

\[ \theta \approx \sin^{-1}(0.4987) \approx 29.9^\circ \approx 30^\circ \]

Therefore, the approximate angle formed between the top of the building and the shadow is 30°.