Math Problem Statement

Find the length of CE (hypotenuse) in the given right triangle CDE where angle C = 17°, adjacent side DE = 1.7, and angle CDE = 90°.

Solution

In this triangle problem, we are tasked with finding the length of CE=xCE = x using the provided right triangle CDE\triangle CDE.

We are given:

  1. CDE=90\angle CDE = 90^\circ (a right angle),
  2. C=17\angle C = 17^\circ,
  3. DE=1.7DE = 1.7 (adjacent side to angle CC).

We can use trigonometric functions since it is a right triangle. Specifically, for the given angle C=17\angle C = 17^\circ, we use the cosine function:

cos(θ)=Adjacent sideHypotenuse\cos(\theta) = \frac{\text{Adjacent side}}{\text{Hypotenuse}}

Step 1: Plugging in known values

  • θ=17\theta = 17^\circ,
  • Adjacent side = DE=1.7DE = 1.7,
  • Hypotenuse = CE=xCE = x.

So:

cos(17)=1.7x\cos(17^\circ) = \frac{1.7}{x}

Step 2: Solve for xx

Rearranging for xx:

x=1.7cos(17)x = \frac{1.7}{\cos(17^\circ)}

Step 3: Calculate the value

We calculate cos(17)\cos(17^\circ) using a calculator:

cos(17)0.9563\cos(17^\circ) \approx 0.9563

Substitute this into the equation:

x=1.70.95631.78x = \frac{1.7}{0.9563} \approx 1.78

Final Answer:

The length of CE=xCE = x is approximately 1.78 units.


Do you need a detailed explanation or further verification?

Here are 5 related questions for deeper understanding:

  1. How do we use the sine function for similar triangles?
  2. What is the tangent function, and when is it used in right triangles?
  3. If the angle changes, how would that affect the hypotenuse?
  4. Can you explain why trigonometric ratios depend on angles?
  5. How do we find missing angles using trigonometric ratios?

Tip: Always use trigonometric functions (sine, cosine, or tangent) based on which sides you are given (opposite, adjacent, or hypotenuse).

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Right Triangles
Cosine Function

Formulas

cos(θ) = Adjacent / Hypotenuse

Theorems

Trigonometric Ratios in Right Triangles

Suitable Grade Level

Grades 9-11