Math Problem Statement

Find the length of AG to 2 decimal places in the given cuboid with angles 27° and 42°, and AD = 63 mm.

Solution

Let’s analyze the problem and solve it.

Step 1: Understanding the diagram

The figure shows a cuboid with the following knowns:

  • AD=63mmAD = 63 \, \text{mm} (along the base).
  • We are asked to find the length of the space diagonal AGAG, which stretches from corner AA to the opposite corner GG.

There are two given angles:

  • DAB=42\angle DAB = 42^\circ (blue angle).
  • BAE=27\angle BAE = 27^\circ (orange angle).

Our goal is to use these angles and the known side ADAD to calculate the length of AGAG to 2 decimal places.


Step 2: Breaking down the triangles

Triangle ABDABD:

We first need to determine the length of the diagonal ABAB, which lies on the base of the cuboid. In right triangle ABDABD, the angle at AA is 4242^\circ, and the side adjacent to it is AD=63mmAD = 63 \, \text{mm}.

Using the trigonometric relation for cosine: cos(42)=ADAB\cos(42^\circ) = \frac{AD}{AB} AB=ADcos(42)=63cos(42)AB = \frac{AD}{\cos(42^\circ)} = \frac{63}{\cos(42^\circ)}

Now, calculate: cos(42)0.7431\cos(42^\circ) \approx 0.7431 AB=630.743184.78mmAB = \frac{63}{0.7431} \approx 84.78 \, \text{mm}


Triangle ABEABE:

Next, we use right triangle ABEABE to find the space diagonal AGAG. The angle BAE=27\angle BAE = 27^\circ, and the side adjacent to it is AB=84.78mmAB = 84.78 \, \text{mm}.

Using the relation for cosine again: cos(27)=ABAG\cos(27^\circ) = \frac{AB}{AG} AG=ABcos(27)AG = \frac{AB}{\cos(27^\circ)}

Now, calculate: cos(27)0.8910\cos(27^\circ) \approx 0.8910 AG=84.780.891095.17mmAG = \frac{84.78}{0.8910} \approx 95.17 \, \text{mm}


Step 3: Final Answer

The length of AGAG is: 95.17mm\boxed{95.17 \, \text{mm}}


Would you like further clarifications or more details on any step?

Here are five follow-up questions:

  1. How would the calculation change if the base side ADAD were different?
  2. What is the formula for a space diagonal in terms of the cuboid's dimensions?
  3. Can we solve for AGAG without using trigonometry?
  4. How can we use vectors to find the length of AGAG?
  5. What if DAB\angle DAB were larger—how would that affect the result?

Tip: When working with multiple right triangles, identify the intermediate values (like diagonal lengths) step-by-step to avoid confusion.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Right Triangle
Space Diagonal
Cuboids

Formulas

cos(θ) = adjacent/hypotenuse
AB = AD / cos(42°)
AG = AB / cos(27°)

Theorems

Pythagorean Theorem
Trigonometric Ratios

Suitable Grade Level

Grades 9-11