An = -4 + (n - 1)(7)
This being in the form of the explicit rule for an arithmetic sequence you can pick out the d and a1.
an = a1 + (n - 1)(d)
d = 7
a1 = -4
Answer:
The shaded shape on the grid is a rectangle. ...
Perimeter of the shaded shape = 3 + 4 + 3 + 4 = 14 units.
Area of the shaded shape = length × width.
Step-by-step explanation:
∠A = 36
∠C =36
∠ADB =72°
∠CBD =36°
∠BDC =108°
Explanation:
AB=AD then ∠ABD & ∠ADB must be equal as they share two lines that are equal so ∠ADB=72°
∠A and ∠C must also be equal (AB=BC)
∠A = 180-72-72=36°
So ∠A & ∠C=36°
∠D=180° (straight line)
So if ∠ADC=72
∠BDC=108° (180-72)
A triangle has 180° so in triangle BDC we have 108° and 36°
So remaining angle (∠CBD) =180-108-36
=36°
This tells us that triangle BDC is isosceles as it has two equal angles ∠CBD & ∠C =36°
