Answer:
base = 15 units
Step-by-step explanation:
We are given area of a triangle = 52.5 sq. units
Height is given as 7 and we have to find the base.
Using formula for area of triangle:
Area of triangle = 
52.5 * 2 = base × 7
105 = base × 7
base = 15
Step-by-step explanation:
There are 5 different positions of 666:
666////
/666///
//666//
///666/
////666
The forward dashes represent any number from 0 to 9.
Case 1: "666////"
Number of ways = 10⁴ = 10,000.
Case 2: The other positions.
Since the 1st forward dash cannot be 0 (leading digit),
Number of ways for each position = 9 * 10³ = 9,000
Number of ways for all 4 positions = 9,000 * 4 = 36,000.
Total evil numbers = 10,000 + 36,000 = 46,000.
P = perimeter = 2L + 2W = 86 cm. Also, L = W + 4. Subst. W + 4 for L,
P = 2(W + 4) + 2W = 86 cm. Then 2W + 8 + 2W = 86 cm, and 4W = 78 cm.
Finally solving for W, W = (78 cm)/4, or 19.5 cm.
If W = 19.5 cm, then L = W + 4 cm = 19.5 cm + 4 cm = 23.5 cm
The rectangle's dimensions are 19.5 cm by 23.5 cm.
