Lesson Example Discussion Quiz: Class Homework |
Step-2 |
Title: Triangles |
Grade: 8-a Lesson: S4-L1 |
Explanation: Let us verify the answer here with the steps. |
Description:
| Step | Type | Explanation | Answer |
|---|---|---|---|
1 |
Problem |
Find the area of an equilateral triangle that has sides equal to 40 cm. |
|
2 |
Hint |
Formula used |
\$"Area of Triangle" = (1/2) \times "base" \times "height"\$ |
3 |
Step |
Side of a equilateral triangle |
\$40 cm\$ |
4 |
Step |
By using the formula, |
\$("hypotenuse")^2 = ("side")^2 + ("side")^2\$ |
5 |
Step |
On Simplification |
\$(40)^2 = h^2 + (20)^2\$ ⇒ \$1600 = h^2 + 400\$ ⇒ \$1600 - 400 = h^2 \$ ⇒ \$h^2 = 1200\$ ⇒ \$h = \sqrt1200 = 34.64\$ |
6 |
Step |
\$"Area of Triangle" = (1/2) \times "base" \times "height"\$ |
|
7 |
Step |
On Cancellation |
\$"Area of Triangle" = (1/\cancel2^1) \times \cancel40^20 \times 34.64\$ |
8 |
Step |
On Cancellation |
\$"Area of Triangle" = 20 \times 34.64 = 69.28\$ |
9 |
Step |
Therefore, the area of an equilateral triangle is |
69.28 cm |
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