# Question on triangometry which one we measure ?

• r-soy
In summary, the conversation discusses using trigonometry to measure the distance A, which is the width of a river. The speaker explains that measuring A or B (the diagonal length) is not the same as measuring the width of a pencil, as it is more practical to measure straight across. The person in the conversation also mentions that the distance A can be calculated, rather than measured directly.
r-soy
see the pic

[PLAIN]http://store2.up-00.com/Oct10/opW54159.jpg

Last edited by a moderator:
She measures 100 m long the bank, and the angle of 35 degrees. Then concludes the distance A using trigonometry. Does that answer your question? If B were required, that could also be done with trigonometry, but it wouldn't be the shortest distance, which most people would be interested in.

This is really just common sense... If asked to measure the width of say, a pencil, you don't start from the left bottom corner of the pencil and measure up to the top right corner, you measure straight across.

The caption on the picture says "To measure The wide of river we measure A or B" Your picture doesn't show it, but the width of the river seems to be A, and we walk 100 m along the river bank. Unless we are able to walk across the river, we don't measure its width (A) or the length of the diagonal (B). These are calculated values, not measured values.

thanks

## 1. What is the purpose of measuring in trigonometry?

The purpose of measuring in trigonometry is to determine the sizes of angles and sides of triangles using various mathematical formulas and ratios.

## 2. What are the three basic trigonometric ratios?

The three basic trigonometric ratios are sine (sin), cosine (cos), and tangent (tan). These ratios are used to relate the sides of a right triangle to its angles.

## 3. How do you measure an angle in trigonometry?

An angle in trigonometry can be measured in either degrees or radians. Degrees are the more commonly used unit of measurement, where a full circle is divided into 360 degrees. Radians are a unit of measurement used in advanced trigonometry and involve using the length of the radius of a circle to measure angles.

## 4. What is the difference between SOH-CAH-TOA and the Pythagorean Theorem?

SOH-CAH-TOA and the Pythagorean Theorem are both used to solve problems in trigonometry, but they involve different concepts. SOH-CAH-TOA is used to solve for angles and sides in right triangles, while the Pythagorean Theorem is used to find the missing side in a right triangle when the other two sides are known.

## 5. How is trigonometry used in real life?

Trigonometry is used in various fields such as architecture, engineering, and physics. It is used to calculate distances, heights, and angles in real-life scenarios, such as measuring the height of a building or determining the slope of a road.

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