Example 4

9.1.4 Example 4

Description

Quick Overview

This section involves calculating the height of a flagstaff and the distance from a point to a building using trigonometric relationships.

Standard

In this example, we use angles of elevation to find the height of a flagstaff atop a 10 m building and the distance from a point on the ground to the building. Utilizing right triangles and the tangent function, we derive both measurements.

Detailed

In this section, Example 4 illustrates a practical application of trigonometry using angles of elevation to find unknown distances and heights. Starting with a point P on the ground, where the angle of elevation to the top of a 10 m tall building (AB) is measured at 30Β°, the distance from point P to the building's base (PA) is calculated using the tangent function. Subsequently, the height of a flagstaff positioned atop the building (BD) is determined with the angle of elevation to the flag's top (AD) measured at 45Β°. By creating two right triangles, the solution employs the relationships of tangent and height to arrive at the required distances. The example emphasizes the practical use of trigonometry in real-life scenarios.

Key Concepts

  • Angle of Elevation: The angle between the horizontal line and the line of sight to an object above.

  • Tangent Function: A crucial concept in trigonometry representing the ratio of the opposite side over the adjacent side in a right triangle.

  • Opposite and Adjacent Sides: Terms that describe the relationship between the sides of a right triangle in relation to a specific angle.

Memory Aids

🎡 Rhymes Time

  • Up to the sky, the angle is nigh, check the height from the ground, let it be found!

πŸ“– Fascinating Stories

  • Once, a student looked up at a tall building, curious about its height. With a straight line of sight, they measured the angle, finding the distant ground, creating triangles in the air.

🧠 Other Memory Gems

  • H-O-A: Height over Adjacent for Tangent’s game!

🎯 Super Acronyms

A for Angle, E for Elevation, T for Tangent β€” remember AET to keep it straight!

Examples

  • Using a 10 m tall building, with an angle of elevation of 30Β°, we find the distance from point P to the building.

  • From the same point, with a 45Β° angle of elevation to the flagstaff atop the building, we calculate the flagstaff's height.

Glossary of Terms

  • Term: Angle of Elevation

    Definition:

    The angle formed between the horizontal line from the observer and the line of sight to a point above.

  • Term: Tangent Function

    Definition:

    A trigonometric function defined as the ratio of the length of the opposite side to the length of the adjacent side in a right triangle.

  • Term: Opposite Side

    Definition:

    In a right triangle, the side opposite the angle of interest.

  • Term: Adjacent Side

    Definition:

    In a right triangle, the side adjacent to the angle of interest.

  • Term: Right Triangle

    Definition:

    A triangle where one of the angles is a right angle (90 degrees).