Question

Joshua finds the perimeter of the following composite figure composed of a square and right triangle so that a braid may be cut around its outer edge. Determine what is wrong with his calculations and how to find the correct length.

Answer 1

The perimeter of a shape is the sum of its side lengths.

Joshua miscalculated the third length of the triangle

First, we calculate the third length (x) of the triangle.

Because the triangle is right-angled, we can make use of Pythagoras.

So we have:

$x^2 = 7^2 + 7^2$

$x^2 = 2(7^2)$

Take square roots of both sides

$x = \sqrt{2(7^2)$

$x = 7\sqrt{2$

The other shape in the figure is a square.

So, the perimeter (P) is

$P = 7 + x + x + x + 7$ ---- i.e. the sum of the visible lengths

So, we have:

$P = 7 + 7\sqrt2 + 7\sqrt2 + 7\sqrt2+ 7$

Evaluate like terms:

$P = 14 + 21\sqrt2$

Hence, Joshua's error is that:

He miscalculated the third length of the triangle

Read more about perimeters at:

brainly.com/question/6465134