A square sheet of paper is folded symmetrically from a corner. If the fold length is 4, what is the area of the triangle formed by the other three corners?

# Tag: area

## The pleasure dome

A semicircle with three squares. The areas of the smaller squares are given. What is the area of the biggest one?

## Twin peaks

A rectangle with three line segments. What is the proportion yellow : red?

## Pyramidion

A triangle containing a semicircle and an equilateral triangle. What fraction is golden?

## The ocean sunset

A semicircle is inscribed in a rectangle. What is the minimal covered fraction?

## Paper hat II

Two overlapping congruent right triangles. If |AB|=15 and |BC|=7, what is the total area?

## En garde

An isosceles triangle with two altitudes dividing each other in segments of length 4 and 5. What is the total triangle area?

## The satellite

A circle containing three squares. What fraction is coloured?

## Distant peaks

Two isosceles triangles and a right angle. What is the proportion green : gold?

## The blue pill

A regular octagon containing a blue hexagon. All line segments have equal length. What fraction is blue?