Step-by-step explanation:
look at the picture !
she has to paint actually 6 rectangles :
the 3 tops of the 3 stairs.
and the 3 vertical front boards (the front of each step of the stairs).
what is the area of these rectangles ? summing up all 6 - that is the surface area to be painted.
each top rectangle is clearly
82×19 (19 cm deep) = 1558 cm²
each front board is
82×12 (12 cm high) = 984 cm²
so, in total we have
3×1558 + 3×984 = 4674 + 2952 = 7626 cm²
as surface area to be painted.
Answer
Step-by-step explanation:
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<u>Given</u><u> info</u><u>:</u><u>-</u> In triangle (∆)ABC , in which ∠A = 2x, ∠B = x+15° and ∠C = 2x + 10°. Then find the value of x , also find the measure of each angles of a triangle.
<u>Explanation</u><u>:</u><u>-</u>
Let the angles be 2x, x+15 and 2x+10 respectively.
∵ Sum of the three angles of a triangle is 180°
∴ ∠A + ∠B + ∠C = 180° [Sum of ∠s of a ∆=180°]
→2x + x+15 + 2x+10 = 180°
→ 2x + x + 2x + 15 + 10 = 180°
→ 3x + 2x + 15 + 10 = 180°
→ 5x + 15 + 10 = 180°
→ 5x + 25 = 180°
→ 5x = 180°-25
→ 5x = 155°
→ x = 155°÷5 = 155/5 = 31.
Now, finding the measure of each angles of a ∆ABC by putting the original value of “x”.
∴ ∠A = 2x = 2(31) = 62°
∠B = x+15 = 31 + 15 = 46°
∠C = 2x + 10 = 2(31) + 10 = 62 + 10 = 72°.
Answer:
correct. the mean of 72 and 89 is 80?5
Step-by-step explanation:
find the mean to confirm it.
(a+b)/2
72+89= 161
161/2=80.5