The sum of 7 angles of a decagon is 1170°. The 3 sides are equal to each other. Calculate the size of the other 3 angles.
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Answer:
Step-by-step explanation:
We are given an isosceles triangle. We need to remember the important rule that the base angles are equal. In this question we need to find the value of 'x' using a perpendicular height of 3 and a base length of 4. In this question we can half the triangle in half to help us find the value of x. Also we need to use Pythagoras theorem to help us find 'x'. Pythagoras states that a² + b² = c² so we want to find the hypotenuse of the triangle. If we half the triangle we get 2 triangle both with a base length of 2 and a perpendicular height of 3 so,
⇒ State Pythagoras theorem
→ a² + b² = c²
⇒ Substitute in the values
→ 3² + 2² = c²
⇒ Simplify
→ 9 + 4 = c²
⇒ Simplify further
→ 13 = c²
⇒ Square root both sides to find the value of 'c'
→ = c
The value of x is the square root of 13