Math Problem Statement

a) Find the length of BC in this right-angled triangular prism. b) Using an exact answer for the length of BC, find the length of BD in this right-angled triangular prism. Give each of your answers to 1 d.p.

Solution

To solve this problem, let's go through each part of the question:

Part (a): Finding the Length of BCBC

From the diagram, we can observe that triangle CFBCFB is a right-angled triangle with:

  • CF=15CF = 15 cm (the base)
  • FB=17FB = 17 cm (the height)

To find the length of BCBC, we can use the Pythagorean theorem: BC=CF2+FB2BC = \sqrt{CF^2 + FB^2} Substituting the values: BC=152+172=225+289=514BC = \sqrt{15^2 + 17^2} = \sqrt{225 + 289} = \sqrt{514} Calculating this gives: BC22.7cm(to 1 decimal place)BC \approx 22.7 \, \text{cm} \quad \text{(to 1 decimal place)}

Part (b): Finding the Length of BDBD

Now that we know BC22.7BC \approx 22.7 cm, we move on to finding BDBD in triangle BCDBCD. In the triangular prism, BDBD forms the hypotenuse of the right triangle BCDBCD, where:

  • BC22.7BC \approx 22.7 cm (calculated from part (a))
  • CD=25CD = 25 cm (as given in the diagram)

Using the Pythagorean theorem again: BD=BC2+CD2BD = \sqrt{BC^2 + CD^2} Substituting the values: BD=(22.7)2+252=515.29+625=1140.29BD = \sqrt{(22.7)^2 + 25^2} = \sqrt{515.29 + 625} = \sqrt{1140.29} Calculating this gives: BD33.8cm(to 1 decimal place)BD \approx 33.8 \, \text{cm} \quad \text{(to 1 decimal place)}

Summary of Answers:

  • Length of BCBC ≈ 22.7 cm
  • Length of BDBD ≈ 33.8 cm

Would you like a detailed breakdown of each calculation step?

Here are 5 related questions that may expand your understanding:

  1. How can the Pythagorean theorem be used in three-dimensional geometry problems?
  2. What are the implications of the Pythagorean theorem in different shapes and prisms?
  3. How can we verify our answers in right-angled triangular prism problems?
  4. Can you determine the volume of this triangular prism with the given lengths?
  5. How would the length calculations change if the prism were not right-angled?

Tip: Always double-check your triangle sides to ensure they form a right angle before applying the Pythagorean theorem.

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Math Problem Analysis

Mathematical Concepts

Geometry
Right-angled triangles
Pythagorean theorem

Formulas

Pythagorean theorem: a^2 + b^2 = c^2

Theorems

Pythagorean theorem

Suitable Grade Level

Grade 9